CompTIA A+ Cert Exam Guide Ch. 7

Question 1

RAM

Answer 1

Random Access Memory

Question 2

DRAM

Answer 2

Dynamic Random Access Memory

Question 3

What purpose does RAM serve?

Answer 3

When an application runs, Windows copies the application to RAM

Question 4

SIMM

Answer 4

Single Inline Memory Module

Question 5

SDRAM

Answer 5

Synchronous Dynamic Random Access Memory

Question 6

DIMM

Answer 6

Dual Inline Memory Module

Question 7

What were the common SDRAM DIMM pin sizes?

Answer 7

Desktops:
• 168-pin

Laptops:
• 68-pin micro-DIMM
• 144-pin micro-DIMM
• 172-pin micro-DIMM
• 72-pin small-outline DIMM
• 144-pin small-outline DIMM
• 200-pin small-outline DIMM

Question 8

What is a bank?

Answer 8

A slot on the motherboard in which a DIMM could fill the 64-bit bus

Question 9

Which SDRAM DIMM chip did not fill the 64-bit bus?

Answer 9

The 32-bit 72-pin SO-DIMM chip

Question 10

What 5 clock speeds were commonly used on early SDRAM systems?

Answer 10

66, 75, 83, 100, and 133 MHz

Question 11

T or F, the SDRAM was tied to the system clock speed so its clock speed matched the frontside bus.

Answer 11

True

Question 12

What is RDRAM?

Answer 12

Rambus Dynamic Random Access Memory

Question 13

What is RIMM?

Answer 13

The letters of RIMM have no meaning. They were a name given to match the names SIMM and DIMM

Question 14

What sizes did RIMMs come in?

Answer 14

184-pin for desktops

160-pin SO-RIMM for laptops

Question 15

What were the speed ratings of RDRAM?

Answer 15

600 MHz, 700 MHz, 800 MHz, or 1066 MHz

Question 16

Explain the dual-channel architecture of RDRAM?

Answer 16

Each RIMM was 64-bits wide, but the RAMBUS MCC alternated between two sticks of RAM to speed up data retrieval. This required that you install RIMMs in pairs.

RDRAM motherboards required all slots to be populated. Unused slots could be filled with continuity RIMM (CCRIMM) to properly terminate the system.

Question 17

What is DDR SDRAM?

Answer 17

Double data rate SDRAM

Question 18

What pin configurations did the DDR SDRAM come in?

Answer 18

Desktops: 184-pin DIMMS
Laptops: 200-pin SO-DIMM or 172-pin micro-DIMM

Question 19

Describe how DDR sticks and chips are named.

Answer 19

First bu the number of bytes per second of data throughput the RAM can handle. This is calculated by multiplying the MHz by 8 bytes. A 400 MHz DDR stick will be named PC3200.

Second by the speed of the DDR chip. DDR400 for a 400 MHz DDR SDRAM chip

Question 20

How does DDR2 gain a speed advantage over DDR?

Answer 20

Clock doubling the input-output circuits on the chips and adding special buffers. This does not speed up the core RAM.

Question 21

What pin configurations do DDR2 RAM use?

Answer 21

Desktop: 240-pin DIMM
Laptop: 200-pin SO-DIMM

Question 22

What pin configuration does DDR3 use?

Answer 22

Desktop: 240-pin DIMM
Laptop: 204-pin SO-DIMM

Question 23

What is SO-DIMM?

Answer 23

Small Outline Dual Inline Memory Module

Question 24

How does DDR3 gain a speed advantage over DDR2?

Answer 24

It doubles the buffer from 4 bits to 8 bits

Question 25

What does XMP refer to in relation to DDR3?

Answer 25

Extended Memory Profile; it enabled power users to overclock their RAM

Question 26

What is triple-channel memory?

Answer 26

Triple-channel memory is a function of DDR3 memory that allows the MCC to alternate between three sticks of RAM, improving performance. You will need three of the same memory modules and a motherboard that supports triple-channel memory.

Question 27

What is a double-sided DIMM?

Answer 27

A RAM stick that has chips on both sides.

Question 28

What does CL refer to in relation to RAM?

Answer 28

CL refers to clock cycle delays. The lower the number (E.g., CL3, CL2) refers to a lower number of clock cycles required before the memory delivers the requested data. CL2 - two clock cycles CL3 - three clock cycles

Question 29

What is parity checking?

Answer 29

Parity (Even and odd) is a check performed by the MCC to validate the accuracy of data sent from RAM. Two methods are used: even and odd parity. A bit would be added to each byte marking it as even or odd based on the number of ones in the byte. The disadvantages of parity are that errors were not always detected, and errors could not be corrected.

Question 30

What is error correction code (ECC)?

Answer 30

A form of error correction what identifies errors in bits of ram and repairs them on the fly.

Question 31

What are signs that you might need more RAM?

Answer 31

1. General system sluggishness | 2. Excessive accessing of the HDD

Question 32

What is a page file?

Answer 32

A portion of the HDD used as an extension of RAM through what's called RAM cache. Also known as swap file and virtual memory

Question 33

What is the recommended size of the page file?

Answer 33

1.5 times the amount of installed RAM

Question 34

How does Windows determine which application to move to the page file?

Answer 34

It looks at the applications running in RAM and chooses the application is used least frequently. When the application is used again, it is loaded back into RAM and another application takes its place in the page file to make room.

Question 35

What is disk thrashing?

Answer 35

Disk thrashing occurs when the computer moves applications back and forth between RAM and the page file quickly. This is typically an indication that you need more RAM.

Question 36

What is ReadyBoost?

Answer 36

ReadyBoost is a feature of Windows Vista and 7 that allows you to use a flash media device as super fast, dedicated virtual memory. The flash device can be anywhere from 1-32 GBs in size. Vista: 1 device 7: 8 devices

Question 37

What is Serial Presence Detect (SPD)?

Answer 37

A technology present in an added chip on a stick of RAM that identifies important information about the RAM allowing the motherboard to setup the RAM for use.

Question 38

What are the two types of parity errors?

Answer 38

Real and phantom

Question 39

How do you recognize a real parity error?

Answer 39

It errors at the same location in memory each time.

Question 40

How do you recognize a phantom memory error?

Answer 40

It errors at different places in memory each time

Question 41

What is a nonmaskable interrupt (NMI)?

Answer 41

An error that occurs that cannot be ignored by your computer, resulting in the BSoD.

Question 42

What methods can you use to test RAM?

Answer 42

1. Purchase RAM testing hardware (expensive option) 2. Replace potentially bad sticks of RAM with known good sticks of RAM 3. Run a software test on the RAM