System Components

Question 1

Form Factors

Answer 1

Motherboards adhere to design specifications called form factors. The form factor determines the physical characteristics of a motherboard, including its dimensions, number of expansion slots, and mounting hole locations, as well as the back panel dimensions, arrangement, and orientation.

Question 2

ATX

Answer 2

The ATX (advanced technology extended) form factor is the most commonly used form factor. Because of its popularity, several variants of the ATX form factor exist. Each variant has different specifications for dimensions and number of expansion slots. However, all ATX variants share the following characteristics:

• Back plate measurements (6.25” × 1.75”)
• Power supply specifications:
  
  • 24-pin ATX power connector
  • On/off switch runs from the case to the motherboard
  • Soft-power control (OS can turn the computer off)
• Expansion slot locations and spacing (0.8” between slots)
• Mounting hole locations
• CPU location (top of board near power supply)

Question 3

Standard ATX

Answer 3

The standard ATX form factor is the form factor that all other variants are modeled after. ATX motherboards:

• Measure 12” × 9.6”
• Have up to seven expansion slots
• Have between six and nine mounting holes

Question 4

Extended ATX

(EATX)

Answer 4

The EATX form factor is the largest ATX variant. EATX:

• Measures 12” × 13”
• Typically uses extra space for additional memory slots

Question 5

microATX

Answer 5

The microATX form factor is a smaller version of the ATX form factor. The microATX form factor:

• Measures 9.6” × 9.6”
• Has four expansion slots

Question 6

ITX

Answer 6

The ITX form factor was designed for low-power, small form factor (SFF) computers. The most common ITX form factor is the Mini-ITX form factor. The Mini-ITX form factor:

• Specifies a maximum motherboard size of 6.7” × 6.7”
• Has only one expansion slot
• Allows for small (100 watt) power supplies
• Is typically used with a home theater PC (HTPC)

Other ITX form factors include the following:

• Nano-ITX (4.7” × 4.7”)
• Pico-ITX (3.9” × 2.85”)
• Mobile-ITX (2.9” × 1.7”)

The Mini-ITX form factor uses the same mounting locations and back panel specifications as the ATX form factor, allowing Mini-ITX motherboards to fit in ATX cases.

Question 7

BTX

Answer 7

The BTX (balanced technology extended) form factor was designed as a replacement for the ATX form factor. However, it did not gain widespread adoption. With BTX:

• The CPU is positioned in such a way that air flow is increased.
• There is no heatsink fan. Instead, a thermal module or shroud fits over the CPU to move heat directly out of the system.
• The back panel orientation and mounting location is reversed.

BTX was implemented mainly by computer manufacturers such as Dell

Question 8

ATX Full-tower

Answer 8

ATX full-tower cases are the largest computer cases. Full-tower cases have a lot of space for external and internal components. ATX full-tower cases are compatible with the following form factors:

• Standard ATX
• EATX
• microATX

Question 9

ATX Mid-tower

Answer 9

ATX mid-tower cases are slightly smaller than full-tower cases. Mid-tower cases have fewer external and internal bays. ATX mid-tower cases are compatible with the following form factors:

• Standard ATX
• microATX
• Mini-ITX
• EATX (some)

Question 10

microATX Tower

Answer 10

microATX towers are smaller cases designed to be placed on desktops. microATX towers typically have only one drive bay and are compatible with the following form factors:

• microATX
• Mini-ITX

Some microATX towers have a slim design. These cases are typically half the width of a microATX tower and are designed to lie flat or upright.

Question 11

Mini-ITX Tower

Answer 11

Mini-ITX towers are designed to house mini-ITX motherboards. They are typically smaller than microATX towers.

Question 12

HTPC

Answer 12

Home theatre PC (HTPC) cases are designed to connect to TVs and be used as a home media computer. HTPC cases are compatible with microATX and Mini-ITX form factors.

Question 13

Notebook

Answer 13

Notebook cases are generally proprietary and often vary among models.

Question 14

When you purchase a computer case, it will usually come with the following components:

Answer 14

• Computer case
• Power supply (although the power supply might also be separate)
• Case fans
• Plastic or rubber feet that attach to the bottom of the case
• Metal screws and standoffs for attaching the motherboard
• Additional external connectors (such as audio, USB, and FireWire) that connect to motherboard headers

Question 15

Power supplies perform the following functions:

Answer 15

• Convert AC power to DC power
  
  • AC (alternating current) is the type of current distributed through wall sockets. The voltage alternates between a negative and a positive charge, which is good for appliances requiring a high current.
  • DC (direct current) is the type of current used inside a computer. Negative particles are drawn toward a positive charge, creating a unidirectional current flow. This type of predictable reliable current is ideal for an application where a lower current is required.
• Provide components with the correct levels of DC voltage
  
  • Standard ATX power supplies provide + 3.3 volts, +/- 5 volts, and +/- 12 volts of DC power. Most modern components require +12 volt output.
  • Each separate voltage output circuit is referred to as a rail and can power multiple devices. To avoid overloading one circuit, many newer power supplies have two or more +12 volt rails. These are known as dual rail power supplies. Separate rails balance the power load between multiple circuits, preventing any one circuit from becoming overloaded.
• Aid in thermal management
  
  • All ATX power supplies have a fan that cools the unit.
  • The fan direction pulls cooler air from the front of the case and blows hot air out the back.

Older ATX units use a reverse air flow that blows air directly over the CPU. This method is not as efficient

Question 16

You should be aware of the following facts about power supplies

Answer 16

• Power supplies should be matched to the motherboard and case form factor (i.e., match an ATX power supply with an ATX motherboard or a microATX power supply with a microATX motherboard).
• Some power supplies have a voltage switch that toggles between two voltage settings. Depending on the country, typically, the voltage switch can be toggled either between 115 and 230 volts, or between 110 and 220 volts.
  
  • 115 volts is used in North America.
  • 230 volts is used in Europe.
  • 100 volts is used in Japan.
  • 220 volts is used in most parts of Asia.

Most modern power supplies eliminate the voltage switch and instead automatically switch between voltages as necessary. These power supplies automatically adjust to accept input voltages in the range of 100 to 240 volts.

• Many power supplies have a switch on the back that turns the power on or off.
• Power supplies are rated in watts. A power supply’s watt rating determines its maximum power output. To determine a computer’s power requirements, use the following method:
  
  1. Find the watt requirement for each component by multiplying volts by amps (W = V × A).
  2. Add each value together to find the total watt requirements.

Alternatively, there are several online tools you can use to estimate a computer’s watt requirements.

• ATX power supplies provide soft power, even when the computer is turned off, the motherboard has power. Soft power allows the computer to be turned on and off by the operating system or over the network.

Question 17

Name and describe the connector

Answer 17

24-pin (20+4 pin) ATX connector

The 24-pin ATX power plug supplies power to the motherboard.

• Some 24-pin connectors have one 20-pin plug and a detachable 4-pin plug. This allows for backwards compatibility with 20-pin motherboards.
• You can plug a 24-pin ATX power plug into a 20-pin motherboard connector, leaving the four pins unconnected.

Older motherboards used 20-pin power plugs. With a 24-pin ATX power plug, the four extra pins supply an additional 3.3, 5, and 12 volts of DC power.

Question 18

Name and describe the connector

Answer 18

4-pin 12 V (P4) power

Starting with the Pentium 4 (P4) processor, CPUs required more power than could be provided through the ATX power plug. The 4-pin 12 V connector:

• Connects to the motherboard
• Provides two dedicated 12 V wires to the CPU (Older processors only used 5 V power)

The 4-pin 12 V CPU connector is not the same as the 20+4-pin ATX power connector.

Question 19

Name and describe the connector

Answer 19

8-pin EPS12V CPU power

Modern processors consume even more power. The 8-pin EPS12V connector provides four lines of 12 V power.

• The 8-pin EPS12V was originally used with some older dual processor systems.
• All modern multi-core processors use this connector.

Some power supplies have two 4-pin connectors (4+4) that are meant to be used side-by-side in the 8-pin plug.

Question 20

Name and describe the connector

Answer 20

6+2-pin PCIe

Newer video cards require more power than can be supplied through the PCI Express bus. The 6+2-pin PCIe connector plugs directly into the video card to supply additional, dedicated power. The 6+2-pin PCIe:

• Provides up to 150 watts
• Is also known as a PEG6+2 (PCI Express Graphics 6+2 pin)

Some motherboards have only a 6-pin PCIe connector. These connectors provide up to 75 watts.

Question 21

Name and describe the connector

Answer 21

4-pin peripheral power

The 4-pin peripheral power connector (colloquially called a 4-pin Molex connector) is used by legacy components (e.g., IDE hard drives and PATA optical drives), case fans, and other accessory devices. The connector provides both 5 V (red wire) and 12 V (yellow wire).

• Each power supply cable typically has multiple 4-pin connectors on the same cable.
• When connecting devices, try to balance the devices connected to each cable

Question 22

Name and describe the connector

Answer 22

SATA power

The SATA power connector has 15 pins and provides 3.3, 5, and 12 volts. As its name implies, it powers SATA devices.

• You can use a special adapter to convert a 4-pin peripheral power connector to a SATA connector.
• When using an adapter, or on some power supplies, the connector supplies only 5 and 12 volts.

Question 23

Name and describe the connector

Answer 23

4-pin mini-Molex

The 4-pin mini-Molex connector provides both 5 and 12 volts and is used by floppy drives.

Most modern power supplies do not have a 4-pin mini-Molex connector.

Question 24

When troubleshooting a power supply, keep the following in mind

Answer 24

troubleshooting a power supply, keep the following in mind:

• Symptoms of bad power supply include:
  
  • The computer does not turn on
  • The computer sporadically shuts off or reboots
  • A broken or noisy fan
• Before opening up the computer, rule out the obvious. Make sure:
  
  • The power cord is plugged into the wall.
  • The power switch is in the on position.
  • The voltage switch is set to the correct voltage.
• Test the power supply using a multimeter or power supply tester. Voltage levels should be within +/- 5% of normal. If they aren’t, the power supply is bad or failing and should be replaced.
  
  • 12 V rail should be between 11.4 and 12.6 volts.
  • 5 V rail should be between 4.7 and 5.25 volts.
  • 3.3 V rail should be between 3.1 and 3.4 volts.
• Because power supplies carry dangerous levels of electrical current, always take proper safety precautions.
  
  • Never ground yourself when working on a power supply.
  • Never open or disassemble a power supply. Always replace the entire unit.

Some computer manufacturers, such as Dell or HP, produce proprietary power supplies. These power supplies might have a unique shape or use different wiring schematics on connectors. When replacing a power supply, identify whether a standard ATX or a proprietary power supply is required.

Question 25

motherboard

Answer 25

A motherboard (also called system board, logic board, or mainboard) is a circuit board that either houses or is connected to all of the components operating in the computer. When selecting a motherboard, consider the following motherboard specifications:

• CPU socket type
• Memory module compatibility
• Number of memory slots
• Maximum supported memory
• Expansion slot count and type
• Onboard devices (video, audio, or network)

Question 26

CPU Socket

Answer 26

The CPU socket houses the CPU. There are a variety of CPU socket types, each of which have unique shapes, pin arrangements, or mounting configurations. Because of this, it’s important to match the motherboard socket type with the processor socket type. Some motherboards support multiple processors and have a socket for each CPU.

Question 27

Memory Slots

Answer 27

Most motherboards have multiple memory slots. Memory slots are designed to be compatible with a specific type of memory module.

Question 28

Expansion Slots

Answer 28

Expansion slots (also called expansion buses) allow you to expand the capabilities of your computer by installing expansion cards. There are a number of different expansion slot types:

• PCI (Peripheral Component Interconnect)
• PCI-X (Peripheral Component Interconnect Extended)
• PCIe (Peripheral Component Interconnect Express)
• Accelerated Graphics Port (AGP)

Question 29

Onboard Components

Answer 29

Many motherboards include onboard components (such as network cards, audio cards, video cards, or USB and FireWire connections). Selecting a motherboard with onboard devices is typically cheaper than buying separate expansion cards for each feature. However, the quality of these onboard devices might not be as high as dedicated expansion cards.

Question 30

I/O Connectors

Answer 30

I/O connectors for onboard components are located on the back of the motherboard. These connectors typically include the following:

• PS/2 mouse and keyboard ports
• USB ports
• Serial ports (COM 1, 2, 3, and 4)
• Parallel port
• Audio jacks
• Ethernet port

An I/O shield fits over the connectors to secure them and protect the inside of the computer from dust and debris.

Question 31

Internal Connectors

Answer 31

There are a number of connectors on motherboards for components such as power supplies, fans, and LED lights. Computer cases often have front panel ports (e.g., USB, FireWire, or audio ports) that need to be connected to the motherboard. These ports are connected to the motherboard’s front panel connectors, which are also called headers.

External ports that are not available on the motherboard are often added using expansion cards.

Question 32

Firmware

Answer 32

The firmware on a motherboard is stored on integrated flash memory. Motherboards use one of two firmware implementations:

• BIOS (Basic Input/Output System)
• UEFI (Unified Extensible Firmware Interface)

Older motherboards stored the BIOS on removable, read-only memory (ROM) chips.

Question 33

CMOS Battery

Answer 33

The CMOS battery is used to keep an accurate date and time, even when the motherboard has no power. In older motherboards, the CMOS battery was also used to retain BIOS configuration settings, which were stored in volatile memory called the CMOS chip.

Question 34

Chipset

Answer 34

The chipset is a group of chips that facilitates communication between the processor, memory, and peripheral devices.

With chipsets:

• The memory controller and graphics controller are on the CPU.
• The remaining functionality is combined into a single controller chip.
  
  • Intel processors use the Platform Controller Hub (PCH).
  • AMD processors use the Fusion Controller Hub (FCH).

The front-side bus is replaced by the Direct Media Interface (DMI).

Question 35

Support manual

Answer 35

A motherboard’s support manual is an excellent source of information. Support manuals contain technical specifications as well as diagrams that identify the motherboard’s components. If you are missing a motherboard’s support manual, check the manufacturer’s website.

Question 36

Motherboard Connectors

Answer 36

Question 37

Use the following process when installing or replacing a motherboard:

Answer 37

1. If you are replacing an existing motherboard, document the current CMOS settings. You might need these settings to configure the new motherboard.
2. Install the CPU, heat sink, and memory before installing the motherboard in the case.
3. Insert the I/O shield into the case.
4. Fasten standoffs to the case, being sure to match the hole pattern on the motherboard. The standoffs prevent the motherboard circuits from touching the system case.
5. Install the motherboard, securing it to the standoffs with insulated washers and screws.
6. Connect the power and accessory cables:
   
   • Connect the ATX power cable and the CPU power cable.
   • Connect the CPU fan power cable.
   • Connect case wires (e.g., power switch, reset switch, and drive activity and power lights).
   • Connect any case fan cables.
7. Connect drives to SATA connectors.
8. Install additional devices in expansion slots.
9. Connect wires for front/top panel ports (e.g., USB, audio, or eSATA).
10. Document the settings of the new motherboard.

Consult the motherboard’s documentation to identify the location and configuration of front/top panel ports and case wires.

Question 38

Common motherboard issues include those discussed in the following table:

Answer 38

Issue

Description

Power Issues

Power supplies wear out over time, especially if they’re overheated or overstressed. If the power supply can’t provide adequate amounts of electricity to the system, the computer may exhibit one of several behaviors:

• It may unexpectedly shut down.
• It may continuously reboot itself.
• It may not power on at all.

Pin 8 on the power supply connector connects to the power good wire on the motherboard. If power disappears off that wire, the motherboard shuts down. If power quickly reappears on that wire, the system may attempt to come back on by itself, resulting in continual reboots. If power does not reappear on this wire, then the system will shut off. For example, a failing power supply may not provide enough voltage on this wire for the system to initially boot up.

If these symptoms are observed, test the power supply to determine if it’s the source of the problem. Turn the power supply on and then test the voltage supplied on either a motherboard connector or on a hard disk connector. If the voltage is less than expected, then the power supply may be at fault. For example, if a 12 volt wire is carrying less than 11 volts, the power supply is probably failing. If this is the case, do the following to rectify the issue:

1. Purchase a new power supply.
2. Remove the old power supply from the system
3. Mount the new power supply.
4. Connect the new power supply to the motherboard and to all other internal devices.
5. Power the system on and verify that the symptoms have been eliminated.

Boot Errors

A malfunctioning motherboard may generate error codes when the system is powered on. Every time the PC boots, it runs a Power On Self-Test (POST) to make sure all of the basic hardware in the system is present and functioning correctly. If a problem is identified during POST, an error is generated. How the error message is reported to the end user depends upon the motherboard manufacturer. The following may be used:

• Audible beeps
• Numeric codes
• Error messages

The actual codes and messages will vary by manufacturer. Check the motherboard documentation for specific details. For example, a numeric 201 error code may indicate a memory problem on some systems, while a 301 error indicates the keyboard did not respond correctly during POST.

Sometimes, a computer system may experience problems (such as a malfunctioning video adapter) that can prevent error messages from being displayed during POST. If this is the case, use a POST card to access POST error codes. Most models use an LED display to report any error codes generated during POST. A POST card is commonly implemented as an expansion board that is inserted into an expansion slot in the motherboard. However, some POST cards also include a USB interface that allows them to be connected to computers that don’t have expansion slots, such as a notebook system.

Distended Capacitors

Over time, the capacitors on the motherboard may become overstressed or overheated. When this happens, they may bulge or even begin to leak fluid. Distended capacitors usually fail at some point, causing the motherboard to fail. For example, if the fans in the power supply spin up when you power on a system, but the motherboard itself doesn’t start, it is possible that capacitors on the motherboard have become distended.

If this happens, inspect the motherboard and look for capacitors that are swollen on top or leaking brown liquid. While it is possible to carefully replace a failed capacitor on the motherboard, it is usually faster and more cost-effective to replace the entire motherboard.

Missing BIOS/UEFI Settings

A constant source of power is required to store the settings configured in the motherboard BIOS/UEFI chipset. The motherboard also needs constant power to keep the system clock running while the system is powered off. Most motherboards implement a small battery that provides this power. If this battery starts to fail, then the following may occur when the system is powered on:

• The system clock loses time.
• Settings configured in BIOS/UEFI are lost.

If this happens, it’s likely that the motherboard battery has failed and needs to be replaced.

Overheating

Internal system components within a computer generate a great deal of heat that must be dissipated. Overheating causes premature component failure. Overheating could be caused by several conditions:

• Inadequate air flow. This may be the result of an inadequate number of fans in the system or fans that are too small. In this situation, additional fans can be added to the system to increase air flow.
• Improperly installed fans. Fans must be oriented to force air through the system in the same direction, otherwise they may fight against each other and prevent air from flowing properly.
• Failing fans. A failing fan moves less air than a properly functioning fan. It’s not uncommon for a failing fan to generate a screeching noise that is caused by worn parts within the fan assembly. This condition can be fixed by replacing the failing fan.
• Dust buildup. Excessive dust within the system can block air flow and cause overheating. Use compressed air or an anti-static vacuum to remove dust buildup.
• Environmental heat. If the air temperature outside the computer is already overly warm, then the temperature inside will be overly warm as well. A properly balanced HVAC system must be implemented in the work area to remove excess heat from the environment.

The internal temperature of computer systems should be monitored. Most motherboards include several sensors that can be used to monitor the system temperature. Usually, the current temperature can be viewed within the BIOS/UEFI setup. There are also software applications available that can read the current temperature values from the sensors and display them on screen. Unlike using a BIOS/UEFI monitoring utility, these tools allow the temperature to be monitored dynamically while the system is in use.

Most motherboards include a thermal shutdown feature. If the system temperature rises too high, the thermal shutdown feature immediately shuts the computer down to prevent component damage. However, it typically does not shut the system down cleanly, so there is a risk of data corruption if this happens.

Intermittent Device Failure

Intermittent device failure occurs when a component occasionally stops working. This usually indicates that the device itself is failing. The best remedy is to replace the failing device because it will fail completely at some point. Immediate replacement prevents this from happening.

Intermittent device failures may also be caused by device drivers that aren’t functioning properly. Device drivers are software and may contain coding errors. Before replacing a device experiencing intermittent failures, first verify that the latest drivers for that device have been loaded. Sometimes downloading the latest driver and installing it will solve the problem. If it doesn’t, then the device itself may need to be replaced.

Smoke or Burning Smell

If smoke or a burning smell is observed coming from a computer, it indicates that electricity is not flowing in the correct manner within the system. If smoke is observed, shut the system off immediately. This issue could be caused by:

• A connector that isn’t seated properly and electricity is arcing between leads.
• A short circuit in the printed circuit board of the motherboard itself or on an expansion board.
• An improperly installed component.

Unfortunately, a component that is smoking has probably already been damaged to some degree. It’s unlikely that it will ever function properly again. Replacement components are usually required.

Question 39

CPU Manufacturer

Answer 39

Intel and AMD are the two major producers of processors used in modern PCs.

• Both Intel and AMD processors work in PC systems and support Windows software.
• Intel has a larger market share, while AMD processors generally cost less.
• Processor performance and special features vary between models and manufacturers.

Question 40

32-Bit or 64-Bit

Answer 40

A 32-bit processor can process 32-bits of information at a time; a 64-bit processor can process 64-bits of information.

• The biggest advantage of 64-bit processors over 32-bit processors is in the amount of memory they can use. 32-bit processors have a limit of 4GB. 64-bit processors have a theoretical limit of 16 EB, although operating system and current hardware limitations impose a much lower practical limit.
• The operating system and applications must be written for 64-bits to take full advantage of 64-bit processing.
• The processor instruction set identifies all instructions (operations) that a processor can perform.
  
  • 32-bit processors use the IA-32 instruction set (also referred to as x86).
  • Itanium processors from Intel use the IA-64 instruction set.
  • AMD64 and Intel 64 processors use the x86-64 instruction set (also referred to as x64).
• 32-bit applications can run on 64-bit processors using the following methods:
  
  • Itanium processors use a software layer to translate between IA-32 and IA-64.
  • x64 processors execute both 32-bit and 64-bit instructions in the hardware.
  • You can run a 32-bit operating system on a computer with a 64-bit processor.
• Applications typically perform better on 64-bit systems.
  
  • 64-bit applications typically perform better than 32-bit applications.
  • In some cases, 32-bit applications might perform better on 64-bit systems.

Question 41

Multi-Core

Answer 41

A multiple core processor has multiple processors within a single processor package.

• Dual-core, triple-core, and quad-core processors are typical in desktop systems.
• Multi-core systems enable the operating system to run multiple applications simultaneously. Without multiple processors, applications appear to run at the same time, but must wait their turn for processing time from the single processor.
• Some applications can be written to execute on multiple processors at the same time.
• Some motherboards use two (or more) processor sockets to provide a multiple processor solution. Multi-core processors use a single motherboard socket to support multiple processors

Question 42

Processor Speed

Answer 42

Processors operate using an internal clock that is the same as, or is a multiple of, the motherboard bus speed. The speed is represented in megahertz (MHz) and is also referred to as the frequency.

• You can purchase processors of the same type but with different speed ratings.
• When selecting a processor, make sure the motherboard supports the processor speed by reading the motherboard documentation first.
• Most motherboards automatically detect the processor speed. If not, you might need to use jumpers or edit the CMOS to configure the processor speed

Question 43

Cache

Answer 43

Cache is memory that the processor can access directly without using the system RAM. There are four types of processor cache:

• Level 1 (L1) cache is integrated on the processor die itself and stores instructions for the processor. On multi-core systems, each processor typically has its own L1 cache. Some processors might have two L1 caches, one for instructions and one for data.
• Level 2 (L2) cache is additional cache used for both instructions and data. Depending on the processor, L2 cache might be shared between two or more cores, or exclusive to a single core.
• Level 3 (L3) cache is additional cache beyond the level 2 cache. For multi-core systems, L3 cache is shared between all cores.
• Level 4 (L4) cache is shared dynamically between the on-die graphics processor unit (GPU) and CPU.

Be aware of the following regarding processor cache:

• The size of the cache increases as you move from L1 to L4, with L1 cache being the smallest.
• As a general rule, a processor with more cache performs better than a processor with less cache (all other things being equal).
• Originally, only L1 cache was on the processor die, with L2 cache being on the motherboard between the CPU and the RAM. As processor technology has advanced, L2 cache moved to the processor die, with L3 cache being on the motherboard. Today, all three cache levels are located on the processor.
• The L4 cache acts an overflow cache for the L3. Information evicted from L3 is dumped into L4

Question 44

Process Size

Answer 44

The process size refers to the manufacturing process used to etch transistors onto the silicon wafer that will become the CPU. A smaller process size means smaller transistors, which translates into a smaller CPU die with more transistors and less power consumption. Process size is expressed in microns (such as .25 microns) or nanometers (90 nm which equals .09 microns).

Question 45

Hyper-Treading

Answer 45

Hyper-threading is a feature of some Intel processors that allows a single processor to run threads (instructions) in parallel, as opposed to processing threads linearly. Hyper-threading enables a processor to execute two threads at the same time. For example, on a quad-core Intel system that supports hyper-threading, the processor can execute 8 threads at a time (2 on each core).

Hyper-threading is not the same as multithreading. Multithreading is a feature of an application that allows it to send multiple threads at the same time. Applications are typically written to support multithreading to take advantage of multiple cores (executing threads on two or more processors at the same time) or hyper-threading features.

Question 46

Throttling

Answer 46

Throttling is the process of modifying the operating characteristics of a processor based on current conditions.

• Throttling is often used in mobile processors to change the operating frequency to minimize power consumption and heat output.
• Throttling can also be used in low memory conditions to slow down the processing of I/O memory requests, processing one sequence at a time in the order the request was received.
• Related to throttling, processors or the operating system can shut down unused cores in multi-core systems to conserve energy

Question 47

Overclocking

Answer 47

Overclocking is pushing a CPU beyond its designed specifications. Overclocking can give you a marginal increase in performance, but will decrease your CPU’s life. Some Intel processors include a Turbo Boost feature. Turbo Boost, the opposite of throttling, allows the processor to dynamically run above its rated speed to improve performance. Unlocked processors are processors whose speed can be changed above their rated speed through overclocking

• With overclocking, you increase the speed and often the voltage to increase the performance of the processor.
• Overclocking typically voids the CPU warranty and could lead to shorter component lifetimes.
• Some multi-core processors (such as a triple-core CPU) have additional cores that have been disabled. With the appropriate motherboard support, you might be able to unlock and use the additional core(s). However, stability of the extra cores is not guaranteed.

Question 49

Mobile Processors

Answer 49

Mobile CPUs are used in mobile computers and cell phones where portability and mobility are a concern. Special versions of processors are built to minimize power consumption and the amount of heat generated.

Question 50

Virtualization

Answer 50

Virtualization is the ability to install and run multiple operating systems simultaneously on a single physical machine. Virtualization typically includes the following components: a physical machine, hypervisor, virtual machine, and virtual hard disk (VHD). The virtual machines appear as self-contained and separate physical systems.

• Virtualization is performed by adding a thin layer of software, called a hypervisor, between the physical system and the operating system. A hypervisor allows virtual machines to interact with the hardware without going through the host operating system.
• Early virtualization was performed using software only. Newer virtualization uses special instructions supported by the processor to improve performance.
• There are several different types of hypervisor software.
  
  • VMware Workstation and ESX (made by VMware)
  • Hyper-V (made by Microsoft)
  • XEN (open source)
• If you are planning on implementing a virtual solution, check to see whether hardware support in the CPU is required. Hardware support is provided by processors with the following features:
  
  • Intel’s Virtualization Technology (VT)
  • AMD’s AMD Virtualization (AMD-V)

Question 51

Integrated Memory Controller

Answer 51

To improve performance, some processors include the memory controller with an integrated graphics processing unit (GPU) on the processor die, resulting in faster memory access by the processor.

Question 52

CPU Cooling

Answer 52

Processors require some form of heat dissipation system to function properly. Without a heat dissipation system, a processor will overheat and burn out in less than a minute. CPUs use a heat sink, fan, thermal paste, liquid, or fanless cooling system to transfer heat from the CPU to the cooling unit.

Question 53

For a long time, processor clock speed was used as a measure of processor performance. This is not necessarily true for newer processors for the following reasons:

Answer 53

• If two processors are of the same type, higher speed typically means higher performance. With processors of different types, speeds might not be comparable.
• It is important to make sure your motherboard can support the speed of your processor.
• Many processors use a performance rating, instead of speed. A higher number indicates a better-performing processor. However, performance ratings are typically applicable only between models of the same manufacturer.
• In some cases, buying a processor with double the cache can nearly double the performance.
• Dual core processors offer better performance, but typically not double. Software must be specially written to take best advantage of the dual core processors.
• Special instruction sets supported by a processor can increase performance. For example, hyper-threading support on Intel processors can boost performance for specific types of operations.
• Performance can also be increased by modifying other system components such as adding more RAM, using a faster disk, or improving cooling and ventilation.
• Overclocking is a feature that causes the processor to operate at a higher speed. Overclocking is typically performed by those who want to get the maximum performance from their systems. Some important things to know about overclocking are:
  
  • Overclocking can cause system instability, component damage, and can void your warranty.
  • Motherboard bus, processor, and memory settings should be adjusted to match the overclock speed.
  • Overclocking may require more voltage.
  • Overclocking often increases heat output. For this reason, it may be necessary to upgrade your cooling devices.

Question 54

Pin Grid Array (PGA)

Answer 54

Pin Grid Array (PGA): PGA processors implement a series of pins on the underside of the processor package in an array. The pins are inserted into corresponding receptacles within the processor socket on the motherboard

Question 55

Land Grid Array (LGA)

Answer 55

Land Grid Array (LGA): The LGA socket moves the connecting pins from the processor package to the socket itself. Conducting pads are implemented on the bottom of the processor that contact the protruding pins from the processor socket

Question 56

Intel processor socket

Answer 56

• 775: Used with the Intel Pentium 4, Celeron D, Intel Pentium 4 Extreme Edition, Pentium D, Pentium Dual-Core, Core 2 Duo, Core 2 Extreme, Core 2 Quad, Xeon, and Celeron processors.
• 1155: Used with the Intel Pentium 4, Celeron, Core i3, Core i5, Core i7, Core i7 Extreme, and Xeon processors.
• 1156: Used with the Intel Pentium 4, Celeron, Core i3, Core i5, Core i7, and Xeon processors.
• 1366: Used with the Intel Celeron, Core i7, and Xeon processors.
• 1150: Used with the Intel Celeron Dual-Core, Pentium Dual-Core, Core i3, Core i5, Core i7, Core i7 Extreme, and Xeon processors.
• 2011: Used with the Intel Core i7 and Xeon processors.

Question 57

AMD processor socket

Answer 57

• AM3: Used with the AMD Phenom II, Athlon II, Sempron, and Opteron processors.
• AM3+: Used with the AMD Phenom II, Athlon II, Sempron, and Opteron processors.
• FM1: Used with the AMD Athlon II processor along with the A-series APUs.
• FM2: Used with the AMD A4 series, A6 series, A8 series, A10 series, Athlon X2, Athlon X4, FirePro, and Sempron processors.
• FM2+: Used with the AMD A4 series, A6 series, A8 series, A10 series, Athlon X2, and Athlon X4 processors.

Question 58

Steps for installing a CPU

Answer 58

Installation Step

Description

Prepare for Installation

Preparing for a CPU installation will help to ensure that your new components are not damaged before installation.

• Use anti-static protection when installing a CPU.
• Ensure that the CPU and motherboard socket type match. The socket identifies the number and layout of pins.
• Verify that the motherboard supports the processor speed.
• Verify how heat connectivity will be established between the CPU and heatsink.

Insert CPU

Inserting the CPU is simple.

• Handle the CPU by the edges without touching the underneath connectors.
• Drop the processor into place, then push down on the lever to lock the processor into place when using a Zero Insertion Force (ZIF) socket that uses a lever to allow installation of the processor.
• Be sure to orient the CPU appropriately with the socket.
  
  • In most cases, the pin array is keyed so that the CPU can be inserted in only one way.
  • For processors that can be inserted multiple ways, be sure to line up pin 1 on the processor with pin 1 in the processor slot. Pin 1 is typically identified with a dot or a triangle.
• Fill unused processor slots with a special terminating resistor when installing a processor in a multi-processor system.
• Be sure that the speed of the processors are the same when adding multiple processors in a multi-processor system, .

Install Heat Sink and Fan

The heat sink and fan are installed on top of the CPU.

• CPUs require a heat sink and most desktop systems also use a fan for cooling.
• When installing a heat sink, use thermal grease or a thermal pad between the processor die and the heat sink. This maximizes heat transfer between the processor and the CPU.

Connect Fan Power

When the CPU includes a fan, be sure to connect the fan power to the motherboard.

Configure CMOS Settings

Most motherboards automatically detect the processor speed. If not, you might need to use jumpers or edit the CMOS to configure the processor speed. For newer processors released after the motherboard, you might be able to add support for the processor by updating the BIOS.

• Typically, the processor will run at a speed lower than its rating if the motherboard does not support the higher speed.
• As a best practice, you should update the BIOS shortly after installing the processor (you must have a processor and memory installed to update the BIOS).

An important feature in the BIOS/UEFI is the Execute Disable Bit. Execute Disable Bit (EDB) is an Intel hardware-based security feature that can help reduce system exposure to viruses and malicious code. EDB allows the processor to classify areas in memory where application code can or cannot execute. When a malicious worm attempts to insert code in the buffer, the processor disables code execution, preventing damage and worm propagation.

To use Execute Disable Bit, you must have a PC or server with a processor with Execute Disable Bit capability and a supporting operating system. EDB-enabled processors by Intel are indicated by a “J” after the CPU model number. Execute Disable Bit is abbreviated as EDB (by Intel) or XDB.

Troubleshoot

Use the following troubleshooting tips if you are having problems with your installation:

• Spontaneous reboot or intermittent system crashes: An overheated CPU will cause a spontaneous reboot or intermittent system crashes. A spontaneous reboot can also be caused by a bad power supply or device driver. A clicking noise when reading or writing data from the hard disk is an early sign of a failing drive.
• System lockups and restarts: Because you have just replaced the processor, the most likely cause of the problem is related to the CPU. System lockups and restarts can be caused by an overheated processor. Make sure the CPU fan is running, and that you have used thermal paste between the CPU and the heat sink.
• System beeps regularly, nothing is shown on the screen and it doesn’t start: Flashing the BIOS is often required to upgrade system components that are part of the motherboard, such as to upgrade to a faster processor. If the motherboard lists the processor as supported but it is not correctly recognized, update the BIOS to the latest version. Before you can do this, you must reinstall the old processor in the system to get it back up and running again. Press F8 while booting to enter the advanced boot menu when Windows loads. However, this option assumes the BIOS has loaded correctly and the computer passed the POST tests. Replacing the motherboard is likely not required as the motherboard was working correctly and the documentation states the CPU is compatible with the motherboard. Replace the CPU only after you have determined that it is faulty.

Question 59

Symptoms of a failed or failing CPU

Answer 59

• System will not boot.
• System boots, but the operating system fails to load.
• System has POST parity problems with a number of devices.
• System locks up shortly after startup:
  
  • This symptom is possibly thermal issue. Check for this problem by shutting down, letting the system cool off, and restarting the computer to verify whether the problem repeats itself. Check the following if overheating seems to be the problem:
    
    • Check the heat sink and fan for placement and condition.
    • Verify that thermal paste or a thermal pad has been used between the processor and the heat sink.
    • Ensure the heat sink is firmly attached to the CPU.
    • Verify that the CPU is properly seated in its socket.
    • Make sure system case fans are working and that the case and expansion slots are in place.
  • If the computer is not overheating but has this symptom, the problem could be the clock or system timers in the BIOS/UEFI are set incorrectly.
• System sounds a POST beep code indicating a CPU fault upon boot:
  
  • Verify that the CPU is receiving sufficient power by checking the power outputs.
  • If these are good, replace the CPU.
  • If the fault remains, the problem is with the motherboard.
• System crashes on startup or when running a software application or certain group of applications:
  
  • Run repetitive tests using diagnostic software.
  • After replacing a seemingly faulty CPU and the symptom remains, run similar tests on the motherboard and chipset.
  • Do not forget to check for a corrupt file in the software.

If the computer boots, but the processor is running at less than its rated speed, check for incorrectly set motherboard settings or use the BIOS/UEFI to set the appropriate CPU speed. If you cannot set the correct speed, try updating the BIOS with the latest version

Question 60

Static RAM (SRAM)

Answer 60

SRAM stores data using four transistors for every bit of data. SRAM does not require constant power to maintain the contents of memory.

• SRAM is more complex and less dense (e.g., lower storage capacity) than DRAM.
• SRAM is faster and requires less power than DRAM.
• Regular SRAM still requires periodic power to maintain the state of memory, but the rate of refresh is less than with DRAM. Non-volatile SRAM (nvSRAM) is able to maintain memory contents when the power is turned off.
• SRAM is typically used in cache memory, such as CPU cache, hard disk cache, and cache in networking devices.

Question 61

Dynamic RAM (DRAM)

Answer 61

DRAM stores data using a single transistor for every bit of data (a 0 or a 1). To maintain the state of the transistor, DRAM must continually supply power to the transistor; when the power is turned off, the data is lost.

• DRAM is simple to implement.
• DRAM can have a very high density (e.g., high storage capacity).
• Because of the simplicity, DRAM is relatively inexpensive.
• DRAM is used in the main system memory on a computer

Question 62

Name this standard for DRAM

Answer 62

DDR

DDR is no longer used in modern motherboards, although you might encounter DDR memory in older systems

DDR (Double-Data Rate Synchronous Dynamic RAM) is a variation of the original synchronous DRAM (SDRAM).

• All variations of DDR are synchronized with the system clock and accept 64-bit words
• DDR accepts a single command and two consecutive data sets per bus clock cycle.
• Operating at the same frequency, DDR has twice the bandwidth of SDRAM.
• DDR operates at 2.5 volts at bus frequencies between 100-200 MHz.

DDR memory has a single notch, slightly off center. DDR memory has 184 pins.

Question 63

Name this standard for DRAM

Answer 63

DDR2

DDR2 doubles the data transfer rate of DDR, for four times the bandwidth of SDRAM.

• DDR2 accepts four consecutive 64-bit words per bus clock cycle.
• DDR2 includes a buffer between the data bus and the memory.
• DDR2 operates at 1.8 volts at bus frequencies between 200-533 MHz. The internal memory frequency is half that of the bus frequency (100-266 MHz).

DDR2 memory differs from DDR memory as follows:

• The notch is slightly closer to the middle.
• It has 240 pins. While you don’t need to count the pins, you should notice that the pins are smaller because they have to fit in the same space as the DDR memory

Question 64

Name this standard for DRAM

Answer 64

DDR3

DDR3 doubles the data transfer rate of DDR2, for eight times the bandwidth of SDRAM (twice that of DDR2).

• DDR3 accepts eight consecutive 64-bit words per bus clock cycle.
• DDR3 operates at 1.5 volts at bus frequencies between 400-1000 MHz. The internal memory frequency is one-fourth that of the bus frequency (100-266 MHz).

DDR3 memory has a single notch more left of center than the notch for DDR or DDR2. Like DDR2, DDR3 has 240 pins

Question 65

Name this standard for DRAM

Answer 65

DDR4

DDR4 doubles the data transfer rate of DDR3 for ten times the bandwidth of SDRAM.

• DDR4 accepts eight consecutive 64-bit words per bus clock cycle.
• DDR4 operates at 1.2 volts at bus frequencies between 1066-2133 MHz. The internal memory frequency is about one-tenth that of the bus frequency (100-266 MHz).
• DDR4 reduces the demand for power.
• DDR4 is not compatible with earlier types of random access memory (RAM) because of the different signaling voltages, physical interface, and other factors.
• DDR4 theoretically allows for DIMMs of up to 512 GB in capacity, compared to the DDR3’s theoretical maximum of 128 GB per DIMM.
• DDR4 memory has a single notch slightly right of center. DDR4 has 288 pins.

Question 66

Name this form factor

Answer 66

DIMM

A DIMM (dual in-line memory module) has pins on both sides of the module, with each pin being unique.

• DIMMs have a 64-bit data path that matches the system bus width.
• RDRAM and DDR/2/3/4 are packaged into DIMMs, with each specification having a unique number of pins and notch position.
• DDR4 allows for DIMMs of up to 512 GB in capacity

Question 67

Name this form factor

Answer 67

144-pin SODIMM and 200-pin SODIMM

A SODIMM (small outline dual in-line memory module) is a smaller DIMM used in laptops.

SODIMMs are much smaller than other memory, perfect for notebook computers. Notice the notch slightly off center in the 144-pin SODIMM. 144-pin SODIMMs are used by SDRAM, DDR, and DDR2 memory. On the 200-pin SODIMM, notice that the notch is farther off center than the 144-pin SODIMM. You might also be able to notice the higher pin density. 200-pin SODIMMs are used by DDR2 and DDR3 memory.

Question 68

Name this form factor

Answer 68

UniDIMM (Universal DIMM) is a specification for DIMMs and is designed to carry DRAM chips. UniDIMMs can be populated with either DDR3 or DDR4 chips, but do not support any additional memory control logic. Because of this, the computer’s memory controller must support both DDR3 and DDR4 memory standards. UniDIMM:

• Is an upgrade to the current SODIMM standard
• Allows mobile platform users to use both DDR3 and DDR4

Question 69

When comparing the speed of memory modules, be aware of the following

Answer 69

• The most useful way to compare most DDR modules will be to compare the amount of data that can be transferred per second (bandwidth), as indicated by the PC- designations. For example, PC-3200 will always indicate a “faster” memory module than one with a PC-2700 rating.
• PC- numbers up to PC-266 identify the frequency (or double the frequency), not the bandwidth. For example, a PC-266 module has a greater bandwidth than a PC-1600 module (PC-266 = PC-2100).
• Comparing DDR- numbers can also give you an idea of the relative bandwidth. For example, DDR-600 can transfer more data than a DDR2-400 module.
• The bandwidth identifies a theoretical maximum that the memory can transfer in a given time period, and is directly related to the front size bus frequency.
• If you can derive the bus frequency, you can also get a relative idea of the amount of data a module can handle.
  
  • When comparing DDR modules, the frequency is relative to the bandwidth.
  • For example, a DDR2 module operating on a 533 MHz bus is faster than a DDR3 module on a 400 MHz bus.
• Other memory characteristics besides the frequency could affect the effective bandwidth or actual speed of the memory module

Question 70

Another method for increasing memory bandwidth is by providing multiple channels within the memory controller. Explain this.

Answer 70

• Dual-channel systems use two memory controllers, while triple-channel systems use three memory controllers. Quadruple-channel (quad-channel) systems use four memory controllers. Each memory controller can communicate with one or more memory modules at the same time.
• To operate in dual-channel mode, install memory in pairs; to operate in triple-channel mode, install memory in sets of three. To operate in quad-channel mode, install memory in sets of four
• Dual-channel systems theoretically double the bandwidth. However, in practice, only a 5–15% increase is gained.
• Dual-channel, triple-channel, and quad-channel support is mainly a function of the motherboard (e.g., the memory controller), not the memory itself. DDR, DDR2, DDR3, and DDR4 can all work in dual-channel systems (depending on the memory supported by the motherboard); both a triple-channel and a quad-channel system use DDR3 and DDR4

Question 71

DDR Bus Speed and Designation

Answer 71

100 MHz

PC-200 or PC-1600 or DDR-200

133 MHz

PC-266 or PC-2100 or DDR-266

166 MHz

PC-2700 or DDR-333

200 MHz

PC-3200 or DDR-400

Question 72

DDR2 Bus Speed and Designation

Answer 72

200 MHz

PC2-3200 or DDR2-400

266 MHz

PC2-4200/4300 or DDR2-533

333 MHz

PC2-5300/5400 or DDR2-667

400 MHz

PC2-6400 or DDR2-800

533 MHz

PC2-8500/8600 or DDR2-1066

Question 73

DDR3 Bus Speed and Designation

Answer 73

400 MHz

PC3-6400 or DDR3-800

533 MHz

PC3-8500 or DDR3-1066

667 MHz

PC3-10600/10666 or DDR3-1333

800 MHz

PC3-12800 or DDR3-1600

900 MHz

PC3-14400 or DDR3-1800

1000 MHz

PC3-16000 or DDR3-2000

Question 74

DDR4 Bus Speed and Designation

Answer 74

800 MHz

PC4-12800 or DDR4-1600

933 MHz

PC4-14900 or DDR4-1866

1066 MHz

PC4-17000 or DDR4-2233

1200 MHz

PC4-19200 or DDR4-2400

1333 MHz

PC4-21300 or DDR4-2666

1600 MHz

PC4-25600 or DDR4-3200

Question 75

Memory is rated based on its guaranteed stable operating frequency and bandwidth (the rate at which data can be read or written). Memory ratings help you to differentiate between slower and faster RAM. The following rating systems are used:

Answer 75

• For all DDR memory (DDR, DDR2, and DDR3), a new designation was introduced to identify that twice the data was being transferred with each bus clock cycle.
  
  • The number following the DDR-, DDR2-, and DDR3- prefixes is the data transfer rate (twice the bus frequency).
  • For example, DDR-400 matches a bus frequency of 200 MHz; DDR2-800 has a bus frequency of 400 MHz; and DDR3-1600 has a bus frequency of 800 MHz.
• For DDR past 150 MHz (and for all DDR2 and DDR3 memory), the PC- designation was changed to identify the bandwidth instead of a number derived from the bus frequency.
  
  • The bandwidth is 16 times the bus frequency, or 8 times the DDR- designation.
  • For example, DDR-400 has a bandwidth of 3200 MB (PC-3200); DDR2-800 has a bandwidth of 6400 MB (PC-6400); and DDR3-1600 has a bandwidth of 12800 MB (PC-12800).
  • For a brief time, the double-frequency designation used the PC- prefix for early DDR modules. For example, PC-200 used with DDR indicates a bus frequency of 100 MHz, not a bandwidth of 100 MB (PC-200 is equivalent to DDR-200 which is equivalent to PC-1600).

Question 76

The best way to ensure that you get the correct RAM for your system is to consult the motherboard documentation. In addition, there are several websites on the internet where you can look up your system or scan your system to find the correct memory type to install. When selecting RAM, consider the following factors

Answer 76

Characteristic

Description

Packaging (Form)

When you are purchasing RAM for a system, the most important consideration is the packaging, also called memory form. The packaging controls both the physical size of the memory module and the memory standard (e.g., DDR2, DDR3, DDR4). If you purchase the wrong type of RAM, it will most likely not fit. If it does, it might have different voltage requirements than what is supported by your motherboard. Memory packaging (memory form) and capacity must match what is supported by the motherboard.

Capacity

The capacity (sometimes called the size) refers to the storage capacity of the memory module (e.g., 256 MB, 512 MB, 1 GB). The total capacity of memory that you can install in your system is limited by:

• The number of memory slots on the motherboard.
• The maximum total capacity that can be installed. For example, most systems will have a maximum capacity of between 3 GB and 16 GB of RAM.
• The maximum module capacity. For example, the motherboard might only be able to accept up to 2 GB or 4 GB modules.
• The maximum amount of memory that can be addressed (used) by the operating system. A 32-bit operating system can use between 3 GB and 4 GB of memory, while a 64-bit operating system can use more.

You can install more than 4 GB of memory in a system that uses a 32-bit operating system; however, the operating system will be able to use only between 3 GB and 4 GB of that memory.

If your motherboard had a total of three slots, with a maximum module size of 1 GB and a system maximum of 3 GB, and if you had two 512 MB modules installed, you would be able to add only a single 1 GB module bringing the total up to 2 GB. You could also replace one or both of the 512 MB modules bringing the total to 2.5 or 3 GB respectively.

Frequency

For optimal performance, you should match the memory frequency (sometimes called the speed) with the frequency supported by the system bus/memory controller.

• You can install slower memory in the motherboard, but this will degrade performance.
• You can install faster memory in the motherboard, but it will operate only up to the maximum supported by the motherboard.
• When you mix memory with different frequencies, all memory will operate at the lowest frequency.
• Most memory modules include an EEPROM chip that identifies its frequency. The BIOS uses the information in this chip to set the frequency automatically.
• On many systems, you can edit the BIOS manually to change the frequency.
• If the BIOS does not configure memory to run at its highest rated speed, then do the following:
  
  • Verify that the motherboard supports that speed. You might be able to update the BIOS to support faster memory.
  • The serial presence detect (SPD) on the memory is often set below the maximum rating for the memory. To use the maximum speed settings, you might need to manually configure the speed and timing settings for the memory (if the motherboard allows you to do this).

CAS Latency

Another factor that affects the performance of memory is the latency associated with accessing data in RAM.

• With a read request, there is a delay between the time the data is requested and the time that the data is available on the module’s output pins. This delay is called the CAS latency (CL).
• Older memory expressed the delay in nanoseconds, but DRAM uses a ratio based on the clock frequency to describe the delay.
• For memory modules of the same type and frequency, a lower CAS number indicates less delay (e.g., “faster” RAM).
• Because CL is related to the frequency, you cannot directly compare the CAS latency between modules with a different frequency. For example, a DDR2 module operating at 533 MHz with a CL of 6 has more delay than a DDR3 module at 667 MHz with a CL of 7.
• In addition to CL, there are other memory characteristics that describe the delay for performing other types of operations. Collectively, these values are referred to as the memory timings.
• For stable operations, the bus must take into account these latencies to keep the bus and the memory synchronized.
• Manufacturers test memory modules and rate them based on the operating frequency and the timing characteristics. Settings that produce stable performance are then encoded into the SPD module on the memory. The BIOS then reads this information to know how to configure memory settings on the motherboard.
• For many systems, you can manually modify the memory timings and frequency. Running RAM at a lower clock speed enables you to decrease the CAS latency setting; increasing the frequency must usually be compensated for by increasing the CL (and other) settings.

Error Correcting Code

Error Correcting Code (ECC) memory is a type of memory that detects and corrects the common kinds of internal data corruption. ECC memory is also called parity memory. Using ECC, a value is appended to the end of each byte so that the value of the data can be compared and recalculated if an error occurs. ECC is an improvement on parity techniques because errors in more than one bit can be detected and corrected.

Keep in mind the following facts about error correcting memory:

• Memory modules with ECC have extra memory chips on the module (typically 9 modules instead of 8). If the number of chips is divisible by 3 or 5, the module is ECC memory.
• ECC or parity memory must be supported by the motherboard.
• Because it is more expensive than non-ECC, ECC memory is typically used only in servers.
• ECC memory is slower than non-ECC memory.
• Do not mix ECC and non-ECC memory in a system. Mixing ECC and non-ECC memory disables the error correction function.

You might hear the terms parity and ECC being used interchangeably. However, parity RAM only checks for errors while ECC RAM checks and corrects errors.

Parity RAM

Parity memory is a type of memory that checks for common kinds of internal data corruption. It does not correct internal data corruption. Non-parity memory does not perform error checking.

Parity RAM is no longer used. Today, PC systems use ECC for error detection and correction.

Buffered (Registered)

Buffered (or registered) RAM has a buffer that holds memory addresses or data before it is transferred to the memory controller.

• Buffered RAM improves stability on systems with a lot of RAM (over 1 GB).
• Buffered RAM might slow system performance.
• ECC modules are typically buffered.
• Buffered RAM must be supported by the motherboard.
• Some motherboards require buffered memory.

Unbuffered memory does not have a buffer to hold memory addresses or data before it is transferred to the memory controller. Unbuffered memory is used in common workstations and laptops. Buffered memory is used in servers and high-end workstations.

Single- or Double-Sided

Single-sided RAM has memory modules that are organized into a single logical bank; double-sided RAM has modules organized into two banks.

• The computer can access data in only one bank at a time. Therefore, single-sided RAM allows access to all of the memory, while with double-sided RAM, the computer must switch between banks.
• Originally, double-sided RAM had modules on both sides of the circuit board, and single-sided RAM had modules on only one side. However, you can also have double-sided RAM with modules on only one side, where the memory is divided into separate banks internally.
• Single-sided memory of the same capacity as double-sided memory uses half the number of memory modules (modules are denser, with a higher individual capacity).
• Some older motherboards are unable to use double-sided memory, while some that allow double-sided memory can use only up to half the total memory when all memory slots are filled, or mixing single- and double-sided together might not be allowed.
• Most motherboards support both single- and double-sided memory. However, verify compatibility before purchasing.

Question 77

When installing memory remember that modules are very sensitive to ESD. Be sure to take proper steps to prevent ESD. View these Memory Installation Facts

Answer 77

• You can add single memory modules to computers that use DDR (including 2, 3, and 4).
• Install memory in the correct slot. Although several memory slots might be open, some system boards require that you use specific slots. Check the system board documentation for more details.
  
  • For many systems, start with the first bank. The first memory bank is often closest to the processor.
  • On some systems you should fill each bank in order.
• Align the memory before inserting, and do not force the module in place. Most memory is keyed to prevent it from being installed backwards or in incompatible slots.
• Most RAM is held in place with small tabs on either end. To remove RAM from a motherboard, push the tabs down to rotate them back, then pull the RAM straight up.
• For a dual-, triple-, and quad-channel configuration:
  
  • Modules must be installed in matching sets (capacity and speed), preferably of the same manufacturer and model.
  • You can typically use different capacity modules between sets. For example, you can use two 1 GB modules as one set and two 512 MB modules in the second set.
  • Install modules in the slots specified in the motherboard documentation. Many motherboards color the slots, with slots used within a set having the same color.

If you install single memory modules, the system will continue to use the memory, but cannot use the memory in dual-channel mode.

• Following installation, power on the system and check for errors. Most BIOS programs include a memory count that displays the total amount of system memory. If it does not count the proper amount of memory, you may have installed the memory incorrectly or you may have a faulty memory module. Also, if the BIOS generates an error between 200 and 299, the error is a memory error.
• Most systems will configure memory settings (frequency, voltage, and timing including latency) automatically based on information in the EEPROM chip. If necessary, edit the BIOS to manually configure memory settings

Question 78

You should be familiar with this list of critical times when memory problems manifest themselves:

Answer 78

• First boot of a new computer. Memory is not properly seated, missing, or the motherboard is defective.
• After a memory upgrade. Ensure that the memory is compatible and was installed and configured properly.
• After software installation. New software requires more memory and can cause problems.
• After hardware installation or removal. Incompletely or improperly installed hardware can cause errors that appear to be memory related.

Question 79

You should be able to identify memory problems and meanings based on the following errors:

Answer 79

Error

Description

The system boot fails and sounds a beep code

Either no memory is installed or the memory was not detected.

The system boots, but the display remains blank

Either a card or memory module is not seated, or the system includes unsupported memory. Non-parity RAM is incompatible with ECC memory and SDRAM is incompatible with EDO memory.

The system boots, but the memory count is incorrect

The POST failed to recognize all of the memory. This can happen with incompatible memory installation. Remember to avoid combining dual-bank with single-bank memory. If any problem is detected during system boot, check the BIOS settings.

The system will check only for memory installed in memory slots on the motherboard. Memory that is on expansion cards or installed on other devices will not be counted and tested.

Error Messages

Memory error usually indicate a failing module or discrepancies between new and old memory. Avoid the latter problem by not mixing new and old memory. Ensure that the memory is functioning properly and is compatible with the system. If the memory is good and fully compatible, these error messages could mean that the motherboard has a problem. The following are some common error messages you may encounter:

• Memory mismatch error
• Memory parity interrupt at x
• Memory address error at x
• Memory failure at x, read y, expecting z
• Memory verify error at x

Software-generated memory problems

Software errors include:

• Registry error - Parts of the registry are written to faulty sections of RAM.
• Exception error - A software bug can cause this type of error.
• General-protection fault - A software bug can cause this type of error.
• Page fault - A software bug can cause this type of error.

For software errors, check to see if the memory address indicated in the error is consistently the same. If so, check the memory. Otherwise, reboot the system or update the software.

Intermittent problems

One of the tougher detection challenges is the intermittent occurrence of error messages, crashes, or sudden reboots. The trouble in diagnosing this situation is the number of potential problems, including timing, heat, corrosion, fluctuating power, loose connections, EMI, or a combination of these problems.

Question 80

Memory problems usually are found in one of the following categories:

Answer 80

• Either more memory is installed than the system supports or the CMOS settings are incorrect
• Incompatible or broken modules
• Improperly installed modules or dirty or defective sockets

Question 81

The following are common signs that a computer needs additional memory:

Answer 81

Symptom

Description

High Disk Usage

Some operating systems send data to the hard disk drive if there is not enough physical memory available. If you hear the hard drive constantly operating as you work, or if the hard drive light on the front of the system case stays illuminated for long periods of time, you may need to add more physical memory to the computer.

Not Enough Memory Errors

If you receive Not Enough Memory or Out of Memory errors when you try to open and use more than one program at a time, you may need more physical memory.

Question 82

Unified Extensible Firmware Interface (UEFI)

Answer 82

The UEFI was designed to replace the BIOS. Important things about UEFI are:

• The UEFI is firmware.
• The UEFI program controls the startup process and loads the operating system into memory.
• The UEFI design improves the software interoperability and the address limitations of BIOS.
• The UEFI provides better security to protect against bootkit (malware attacks on the boot process) attacks.
• The UEFI provides faster startup times.
• The UEFI supports drives larger than 2.2 terabytes.
• The UEFI supports 64-bit firmware device drivers.
• The UEFI is compatible with both BIOS and UEFI hardware.
• You should frequently check for UEFI updates from the manufacturer. Updating the UEFI (called flashing the UEFI) makes new features available.

Question 83

Basic Input/Output System (BIOS)

Answer 83

The BIOS is a legacy program stored in a read-only memory (ROM) chip that the CPU automatically loads and executes when it receives power. Important things to know about the BIOS are:

• The BIOS program controls the startup process and loads the operating system into memory.
• The BIOS is firmware.
• You should frequently check for BIOS updates from the manufacturer. Updating the BIOS (called flashing the BIOS) makes new features available, such as allowing the BIOS to recognize newer hardware devices.
• Most BIOS chips vary from 265 KB to 1 MB in size.
• Video cards include a BIOS chip on the device. These devices have their own ROM chip called an option ROM (OpROM).

Question 84

Electrically Erasable Programmable Read-Only Memory (EEPROM)

Answer 84

The EEPROM is a RAM chip that replaced the CMOS chip. Important things about EEPROM are:

• EEPROM is a type of non-volatile memory used in computers and other electronic devices to store relatively small amounts of data.
• EEPROM allows individual bytes to be erased and reprogrammed.
• EEPROM replaced EPROM chips and are used for computer BIOS built after 1994.
• EEPROM chips allow you to update the BIOS/UEFI in your computer without having to open the computer and remove any chips.

Question 85

Complementary Metal-Oxide Semiconductor (CMOS)

Answer 85

CMOS is legacy computer chip technology that has become a general term used for the program that stores important system information related to the starting of a computer. It is often used synonymously with BIOS. Data held in CMOS includes the hard disk type and configuration, the order of boot devices, and other configurable settings related to the system hardware. The following are important things to know about CMOS:

• You changed the data stored in CMOS using a CMOS editor program that was part of the BIOS.
• CMOS used to refer to the real-time clock and the CMOS chip that stored system information. Both were powered by a CMOS battery. Now, the EEPROM chip stores the system information that used to be stored on the CMOS chip. EEPROM requires no power to maintain data storage.
• The CMOS battery is still used to keep the real-time system clock running when the computer is powered off. It can be a low-voltage dry cell, lithium mounted on the motherboard, or even AA batteries in a housing clipped on a wall inside of the case. The electric current is about 1 millionth of an amp and can provide effective power for years.

Question 86

Common reasons for editing the CMOS settings are

Answer 86

• To change the boot device order.
• To enable or disable motherboard devices.
• To add a password to the setup program to prevent unauthorized access.

If you set a BIOS/UEFI password and then forget it, you will be unable to edit CMOS settings.

To remove the password for most motherboards, move or remove a jumper, then replace it after a specific period of time.

• To configure processor or memory settings (e.g., when you need to set operating speeds or when you want to overclock hardware settings).
• (In rare cases) To manually configure device properties for legacy devices

Question 87

One of the main jobs of the BIOS/UEFI is to help start the system. The following process is used when you turn a computer on:

Answer 87

1. Power is supplied to the processor. The processor is hard-coded to look at a special memory address for the code to execute.
2. This memory address contains a pointer or jump program which instructs the processor where to find the BIOS program.
3. The processor loads the BIOS program. The first BIOS process to run is the power-on self-test (POST) process. POST does the following:
   
   1. Verifies the integrity of the BIOS/UEFI code.
   2. Looks for the BIOS on the video card and loads it. This powers the video card and results in information being shown on the monitor.
   3. Looks for BIOS programs on other devices, such as hard disk controllers and loads those.
   4. Tests system devices, such as verifying the amount of memory on the system.
4. After POST tests complete, the BIOS identifies other system devices. It uses CMOS settings and information supplied by the devices themselves to identify and configure hardware devices. Plug-and-play devices are allocated system resources.
5. Then the BIOS searches for a boot drive using the boot order specified in the CMOS.
6. On the boot device, the BIOS/UEFI searches for the master bootloader, then loads the bootloader program. At this point, the BIOS/UEFI stops controlling the system and passes control to the bootloader program.
7. The bootloader program is configured to locate and load the operating system.
8. As the operating system loads, additional steps are taken to load all additional programs and configure devices for use by the operating system.

Question 88

Expansion cards

Answer 88

Expansion cards are used to expand a computer’s functionality or increase its performance. Expansion cards are installed into the expansion slot on a motherboard. Expansion cards and slots use different expansion bus standards that define communication specifications as well as physical characteristics.

Question 89

Peripheral Component Interconnect (PCI)

Answer 89

PCI was developed to replace the obsolete ISA and VESA bus standards. PCI:

• Is processor independent, meaning the CPU and PCI bus can process concurrently
• Supports plug-and-play, meaning installed devices are detected and configured automatically
• Is used most commonly by devices such as sound cards, modems, network cards, and storage device controllers
• Can run at 33 MHz and transfer data at 133 MBps or run at 66 MHz and transfer data at 266 MBps

Question 90

PCI Express (PCIe)

Answer 90

PCIe was developed to replace PCI, PCI-X, and AGP. Instead of a shared bus, each PCIe slot links to a switch that prioritizes and routes data through a point-to-point dedicated connection and provides a serial, full-duplex method of transmission. PCIe uses several different connection types.

• PCIe types are defined by the number of transmission lanes that are used to transfer data. For example, PCIe x1 provides one lane for transmission (x1), while PCIe x16 provides sixteen lanes for transmission. PCIe defines x2, x4, x8, x16, and x32 connection types.
• PCIe data rates depend on the protocol version and number of transmission lanes:
  
  • 1.0: 250 MBps (x1); 4 GBps (x16)
  • 2.0: 500 MBps (x1); 8 GBps (x16)
  • 3.0: 1 GBps (x1); 16 GBps (x16)
  • 4.0: 2 GBps (x1); 32 GBps (x16)
• In addition to greatly increased speed, PCIe offers higher quality service.
• PCIe can run alongside legacy PCI technology (e.g., both PCIe and PCI buses can be in the same system).
• PCIe x1 slots are typically used for network cards, USB cards, and sound cards. PCIe x16 slots are primarily used for dedicated video cards.

PCIe cards are cross-size compatible, as long as the slot size is the same or larger than the card size. For example, a PCIe x1 card can be installed in a PCIe x16 slot, but a PCIe x16 card cannot be installed in a PCIe x1 slot

Question 91

Legacy buses

Answer 91

Buses that have been replaced by newer types are considered legacy buses. Legacy buses are rarely used and include the following:

• AGP (accelerated graphics port) was a dedicated bus type used by dedicated video cards.
• AMR (audio/modem riser) was a riser card that attached to the motherboard and allowed additional cards (called daughter cards) to be installed.
• CNR (communications network riser) was a riser card slot that allowed for installing network, sound, or modem functions.

Question 92

Video cards can be implemented as a dedicated expansion board or integrated with other components (e.g., the motherboard or CPU). Describe each.

Answer 92

• Dedicated video cards:
  
  • Are installed in an expansion slot on the motherboard
  • Have a graphics processing unit (GPU) and a dedicated, high-speed video memory bank
  • Are more powerful than integrated video cards, but are also more expensive
• Integrated graphics:
  
  • Integrate the GPU with another hardware component (e.g., a motherboard or CPU)
  • Share system memory for graphic processing
  • Are much cheaper than dedicated video cards, but are also less powerful

Question 93

Display Connectors

(Video Cards)

Answer 93

Video cards have one or more connectors for attaching an external display. Always try to select a video card with connectors that match your display.

• VGA monitors use a VGA (DB-15) connector.
• LCD and LED monitors use one (or more) of the following connectors:
  
  • DVI-Integrated (DVI-I) connector
  • HDMI connector (also used by HDTVs)
  • DisplayPort connector

DVI-I connectors are able to send either analog or digital signals. Older video cards might use DVI-A (analog) or DVI-D (digital) connectors.

Some video cards have dual heads (two output connectors capable of displaying video simultaneously) and are able to support dual monitors

If necessary, you can use special connector adapters to convert from one connector type to another (e.g., DVI to HDMI). However, it’s usually best to match the connector type of the video card with the display connectors

Question 94

Display Quality

(Video Cards)

Answer 94

The quality of images and animations is determined by both the video card and the external display. When selecting a video card, the following specifications should be considered:

• The resolution is the number of pixels displayed on screen. A higher resolution means that more information can be shown on the screen. A video card is rated by its max resolution, which is the highest possible resolution it can display (e.g., 1920 × 1080 or 4096 × 2160).
• The refresh rate is the number of times in one second that the GPU draws a frame. Refresh rates are measured in hertz. A refresh rate of 70 Hz or lower may cause eye fatigue. An optimal refresh rate is between 75 Hz and 85 Hz.

For optimal image quality and graphic performance, it is best to select a display that matches the video card specifications, and vice versa

Question 95

Processing Capabilities

(Video Cards)

Answer 95

The graphics processing unit (GPU) handles all video rendering tasks. GPUs are much more efficient at processing graphic data than a traditional CPU.

• Using the GPU to render graphics is often referred to as video hardware acceleration.
• Settings in the operating system can be used to control how much video processing is offloaded to the GPU.
• GPUs have a clock speed that is rated in MHz. A higher speed means better performance

Question 96

Memory

(Video Cards)

Answer 96

Dedicated video cards use high-speed memory to store graphic data. The amount of memory on the card affects performance as well as other characteristics.

• The amount of memory on a card can be as low as 1 GB or as high as 12 GB.
• Dedicated video cards use the following types of memory:
  
  • DDR, DDR2, and DDR3 memory are similar to system memory. This type of memory is cheaper, but provides less performance features than special graphics memory.
  • GDDR2, GDDR3, and GDDR5 are DDR memory specifically designed and optimized for graphical data. This memory is more expensive, but results in better performance.

Integrated graphics (onboard video cards) share system memory with the CPU for video processing

Question 97

Bus type

(Video Cards)

Answer 97

Video cards must be compatible with the expansion slots on the motherboard. Common slot types used by video cards include the following:

• PCIe x16
• PCI
• AGP and VESA (used by older video cards)

Motherboards with integrated graphics embed the functionality with the buses on the system (e.g., PCIe, AGP, or PCI)

Question 98

Multi-GPU

(Video Cards)

Answer 98

Some video cards can be linked together and share the graphic processing load between the two GPUs.

• Multi-GPU configurations are manufacturer-specific:
  
  • NVIDIA uses SLI (Scalable Link Interface).
  • AMD uses CrossFire.
• Video cards are linked using a special bridge clip or through software (depending on the implementation).
• The motherboard and each video card must use the same connection method (SLI or CrossFire). The motherboard must also have multiple PCIe x16 slots.
• In most cases, both video cards must be identical.

Some motherboards allow you to link an integrated graphics controller with a video card installed in the expansion slot; however, this offers a negligible performance boost

Question 99

HDMI audio

(Video Cards)

Answer 99

HDMI cables are able to carry both video and audio signals; however, most video cards send only a video signal. The following techniques can be used to send an audio signal through the video card:

• With audio pass-through, an audio output cable is connected to the video card. The video card combines the audio signal with the video signal for HDMI output. This option is often called HDTV out.
• A graphics card with an onboard audio processor can decode and process audio and send it out the HDMI port. This option is often referred to as onboard sound.

Question 100

DirectX/OpenGL

(Video Card)

Answer 100

DirectX is a collection of application program interfaces (APIs) that improves graphic, animation, and multimedia creations.

• DirectX includes multiple components targeted to a different aspect of multimedia. For example, Direct3D is the 3D rendering component of DirectX.
• Applications (typically games) are written using features included in specific DirectX versions.
• To view content written to a specific DirectX version, your video card must also support that (or a higher) version.

OpenGL is an alternative standard to DirectX that is used by some applications. Most video cards support both DirectX and OpenGL.

Question 101

High-bandwidth Digital Content Protection (HDCP)

(Video Cards)

Answer 101

HDCP is a method for protecting digital media. The purpose of HDCP is to prevent the interception and copying of protected data streams as they are sent from a playback device to a display device (e.g., from a DVD player to an HDTV).

• When playing protected content from a PC, the DVD player, video card, and display device must all support HDCP.
• If you plan on watching protected content on your PC, or playing content from your PC to an external TV, make sure the video card supports HDCP.

Question 102

Use the following process to install a dedicated video card:

Answer 102

• Video cards must be compatible with the expansion slots on the motherboard.
• If the motherboard has integrated graphics, disable it in the CMOS configuration when installing a dedicated video card.
• Install the video card in the first open expansion slot.
• If using a multi-GPU configuration (SLI or CrossFire):
  
  • Install the secondary video card in the next open expansion slot.
  • Link the two video cards together using the bridge clip.
• Connect any additional power connectors to the video card(s) (e.g., 6-pin or 8-pin auxiliary power).

Some motherboards have an additional power connector near the expansion slots that are used with multi-GPU configurations.

• Connect the external display to the video card using the appropriate cable. When using a multi-GPU configuration, connect the monitor to the primary (first) video card.
• After installing the video card and making all necessary connections, turn on the computer.
• In the operating system, install the video card drivers.
• If using a multi-GPU configuration, install all necessary configuration software.

Question 103

Sound Card Components

Answer 103

Because computers use digital data, sound cards must convert analog sound into digital data, and digital data into analog sound. The following components are used to do this:

• The Analog-to-Digital Converter (ADC) converts analog sound into digital data.
• The Digital Signal Processor (DSP) is an onboard processor that handles analog and digital conversion.
• The Digital-to-Analog Converter (DAC) converts digital data into analog sound (in preparation to be played on speakers).

When purchasing a sound card, be aware of the following considerations:

Component

Description

Bus Support

Sound cards can be installed via an expansion slot (e.g., PCI or PCIe x1) on the motherboard. When selecting a sound card, make sure the bus type is compatible with your motherboard.

Most new motherboards have an onboard sound card.

Channels

Audio can be split into multiple channels, which increases the sound quality and makes it more realistic. Some standard channel configurations are as follows:

• 2 channel audio is stereo. Examples of 2 channel audio include standard TV and radio.
• 4 channel audio is quadraphonic audio and was an early attempt at surround sound.
• 5.1 channel audio, also known as surround sound, has 6 audio channels: five speakers and one low-frequency effects subwoofer (LFE) channel.
• 7.1 channel has 8 audio channels: 7 speakers and one LFE subwoofer channel. This is the first technology providing error correction.

Sampling Rate

The sampling rate is the number of analog signal samples taken in over a period of time. Sample rates are expressed in cycles per second, called hertz (1,000 hertz (Hz) = 1 kilohertz (kHz)). A high sampling rate gives a more accurate representation of the sound. Examples of different sampling rates include:

• 8 kHz (telephone) This is adequate for conversation because the human voice’s full range is about 4 kHz.
• 22 kHz (radio quality).
• 44 kHz (CD quality) This sample rate can accurately reproduce the audio frequencies up to 20,500 hertz, covering the full range of human hearing.
• 48 kHz (Digital TV, DVD movies).
• 96 kHz (DVD audio).
• 192 kHz, used by:
  
  • LPCM (Linear Pulse Code Modulation), a DVD-music production format.
  • BD-ROM (Blu-ray Disc-ROM).

Higher sample rates require more bits of data per sample.

• 8-bit sound cards use a sampling size of 256.
• 16-bit sound cards use a sampling size of 65,536.
• 20-bit sound cards use a sampling size of 1,048,576.
• 24-bit sound cards use a sampling size of 16,777,216.
• 32-bit sound cards use a sampling size of 4,294,967,296.

The bit portion of a sound card’s sampling size does not correspond with the bus size.

Feature Support

Additional features on sound cards provide higher quality sound or additional functionality.

• DirectSound 3D allows a computer to play audio in surround sound.
• EAX is a high-definition sound technology originally developed for video games. This technology provides such realistic nuances that audio can actually cue gamers.
• THX is a sound quality standard, originally created for film, now available on sound cards. This is a sound card feature that allows computers to present theater quality sound output.
• Dolby Digital is a technology that broadcasts sound at a frequency the human ear can hear and diminishes collateral sound. This is a sound card feature that allows computers to present higher quality sound output.
• DTS (Digital Theater Systems) Digital requires an optical reader to decode physical data and send it to a computer for processing. This is a sound card feature that allows computers to present theater quality sound output.
• SDDS (Sony Dynamic Digital Sound) was originally developed for theater sound. SDDS decoders provide error correction.
• MIDI (Musical Instrument Digital Interface) is a protocol for recording and playing audio created on digital synthesizers. This feature allows the computer to become an integrated component to a musical instrument.

Analog Input and Output

Analog output jacks allow you to play sound on your computer through external devices:

• The speaker out connector sends signal to external speakers. This signal is amplified and the computer controls the sound level that is sent.
• The line out connectors send audio to other sound devices. This signal is unamplified.

Analog input jacks allow you to record audio through the sound card.

• The line-level (line-in) connector receives signals from CD players and musical instruments coming from the line out port of the other device.
• The mic-level (mic in) connector receives signals from a microphone.

Digital Audio

Most audio devices, such as stereo consoles, TVs, and speakers require analog audio. Newer devices, such as some CD players, DVD players, and HDTVs, are capable of processing digital audio signals. Digital audio support in a sound card:

• Allows you to play digital audio directly from an internal CD player
• Allows for compression of audio data to support Dolby Digital or DTS surround sound
• Can use fiber optic cables to eliminate electrical interference

Sound cards support digital audio in the following ways:

• An internal connector on the sound card connects to a digital audio output connector on a CD/DVD drive. Through this connection, you can play CDs directly through the sound card.
• An internal connector on the sound card sends HD audio, such as from a DVD or Blu-ray disc, to an audio pass-through on a video card. This allows the HD audio signal to be combined with the video signal through an HDMI connector.
• Sony/Philips Digital Interface Format (S/PDIF) is a consumer standard for digital audio. These are either optical or coaxial external connectors and allow input and output between other digital audio-capable devices.

Additional Ports

In addition to audio input and output ports, some sound cards also include the following ports:

• MIDI port to interface with MIDI sound devices
• FireWire
• Some high-end audio cards include HDMI video processors and video output, combining the features of an audio card with a video card. The sound card might have 1 or 2 HDMI ports (for input and/or output).

Question 104

Sound card drivers and other software save digital audio into several different file types. Common file types include

Answer 104

• WAV (Windows standard), a widely used and compatible file type
• AIFF (Audio Interchange File Format), the Macintosh equivalent of the WAV
• AU (UNIX standard), supported by most web browsers
• MP3 (MPEG-2 Layer III), a highly effective audio compression standard
• AAC (Advanced Audio Coding), also known as MPEG-2, a compression expected to replace MP3
• WMA (Windows Media Audio), a highly compatible standard developed to compete with Real Audio
• MIDI, not a true audio file, but contains data to reproduce sounds through electronic synthesis

Question 105

Be aware of the following when configuring system sound:

Answer 105

• Many motherboards include an onboard sound card. Use the connectors on the motherboard’s I/O plate to connect components to the onboard sound card.
• Sound cards are typically added to a computer using PCI or PCIe slots. Some sound cards also connect through USB. External sound cards for laptops can use an ExpressCard slot.
• When installing a sound card using an expansion slot, make sure to disable the onboard sound card in the CMOS configuration.
• After installing the sound card, install the drivers and other software that came with the sound card.
• In Control Panel, use the Sound applet to:
  
  • Configure settings for sound card connections such as speakers, audio input, and microphone.
  • Identify the sources that you want to record.
  • Configure sounds to play with system events or to play a sound to test your configuration.
• An audio codec is a specific method of formatting sound files. Common codecs include WAV, WMV, AIFF, and MP3. To play sounds saved using these formats, your computer must have the corresponding codec installed.
  
  • You can see the list of installed codecs in System Information.
  • By default, Windows comes with common codecs installed. Other codecs might be installed as you add other software

Question 106

To troubleshoot sound problems, try the following:

Answer 106

• Make sure that the speakers are connected to the sound card and that the speakers have power.
• Check the volume setting on the speaker and the back of the sound card (if present).
• Check software sound settings. Verify that the sound is not muted and check mixer settings.
• If some files play but others do not, make sure you have the right codecs installed for playing that file type.
• If you are working with a built-in audio interface, verify that it is correctly configured in the BIOS. If you have installed an add-in card, make sure the built-in audio is disabled.
• If no sound plays, make sure the card is seated, check for resource conflicts, and update the drivers if necessary.
• Ensure that the sound card is not experiencing electromagnetic interference (EMI) from the disk drive or power supply. To remedy this problem, move the affected card to an expansion slot located away from the source of EMI

Question 107

Answer 107

Mini TRS ports on the sound card accept 3.5mm plugs for analog audio I/O. The number of ports on the sound card depends on the type of I/O support (e.g., the number of speaker channels, microphone, or line-in support).

Ports are often labeled with text or graphics to identify its function. Standardized color coding might also be helpful in determining the proper connection.

• Pink = Mic in (mic-level)
• Light blue = Line in (line-level)
• Lime green = Line out (front speakers or headphones)
• Black = Line out (rear speakers)
• Orange = Line out (center and subwoofer)

Although these colors are standard, be sure to consult the sound card documentation for specific details.

Question 108

Answer 108

A TOSLINK (or optical audio cable) connector is used with digital optical I/O for S/PDIF audio.

Question 109

Answer 109

An RCA connector on a sound card is used for coaxial digital I/O for S/PDIF audio.

While RCA connectors can be used for analog audio, RCA connectors on a sound card are normally used for S/PDIF digital audio.

Question 110

Answer 110

Some sound cards include one or more IEEE 1394 (FireWire) ports. These ports function as normal IEEE 1394 ports.

Question 111

Answer 111

A sound card with an HDMI port is capable of sending HD audio to an HDMI device. Some sound cards are able to output video or combine a video signal from a video card and output the combined audio/video signal through the HDMI port.

Question 112

Because proper airflow is necessary to keep components cool, consider the following recommendations to ensure optimal system cooling:

Answer 112

• Keep the case free of dust and debris. Excess dust can restrict airflow and prevent proper heat transfer.
• Reduce the number of airflow obstructions.
  
  • Employ proper cable management (e.g., bundle cables together and secure unused cables to the case).
  • Space out multiple hard disk drives instead of stacking them next to each other.
  • Do not use an excess number of expansion cards.
• Maintain appropriate ambient temperatures. Optimal ambient temperatures are between 60 and 80 degrees Fahrenheit. For server rooms, the ambient temperature might be as low as 45 degrees.
• Ensure proper ventilation.
  
  • Keep air intakes and exhausts free from obstructions.
  • Leave space between the computer and any walls or desks.
• Preserve negative pressure inside the case by keeping all covers and shields installed (e.g., unused expansion cards, I/O shield, front drive bays).

Question 113

The following diagram shows how air should flow through a computer case

Answer 113

Question 114

Case fans

(Cooling)

Answer 114

Case fans create a pressurized system that allows air to flow through the case in a specific way.

• Intake fans (at the front) pull air inside the case to cool components.
• Outtake fans (at the back and top) exhaust warm air from inside the case.
• Some cases have intake fans on the side case cover.
• Fan filters can be installed to keep dust and debris inside the case to a minimum.

Question 115

Power supply

(Cooling)

Answer 115

ATX power supplies aid in cooling by exhausting hot air out the back of the case.

Question 116

Heat sink

Answer 116

Heat sinks are made of a heat conductive material (usually aluminum or copper) and are attached to components using a thermal paste or pad. Heat sinks are designed with fins to increase the surface area exposed to air, allowing heat to dissipate from the component much faster. Heat sinks can be either active or passive.

• Active heat sinks have an attached fan that helps cool off the component at a faster rate. Active heat sinks are used with the following components:
  
  • CPUs
  • High-end video cards
  • Some motherboard chipsets with integrated graphics
• Passive heat sinks do not have a fan and instead rely on increased surface area and passive air movement to cool the component. Passive heat sinks are used with the following components:
  
  • Most motherboard chipsets
  • Low-end video cards
  • Memory modules (heat sinks on memory modules are also called heat spreaders)

Because passive heat sinks do not use a fan, they are 100% reliable. However, active heat sinks can dissipate heat much faster than passive ones

Question 117

Heat sensors

(Cooling)

Answer 117

Most motherboards include the following heat sensors:

• CPU sensor (located on the circuit board underneath the processor)
• System case sensor (located either on the motherboard or on a cable attached to the motherboard)
• Room temperature sensor (usually connected to the motherboard by a cable and mounted on a case slot)

Special software can monitor the temperature levels and be configured to send warnings when high temperature conditions exist. The BIOS in most motherboards can also be configured to automatically shut the system down when a specified thermal threshold is exceeded

Question 118

Liquid cooling

Answer 118

Liquid cooling systems are used when air cooling is not sufficient. Liquid-based cooling systems are composed of tubes, cooling plates, a reservoir, and a radiator. Cooling plates have tubes connected to them and are attached to components. Liquid coolant is then circulated through the system, cooling it. Because liquid cooling can dissipate heat much faster than air cooling, it is primarily used for high-end gaming computers and high-performance systems