CompTIA A+ Cert Exam Guide Ch. 7 Flashcards
RAM
Random Access Memory
DRAM
Dynamic Random Access Memory
What purpose does RAM serve?
When an application runs, Windows copies the application to RAM
SIMM
Single Inline Memory Module
SDRAM
Synchronous Dynamic Random Access Memory
DIMM
Dual Inline Memory Module
What were the common SDRAM DIMM pin sizes?
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
What is a bank?
A slot on the motherboard in which a DIMM could fill the 64-bit bus
Which SDRAM DIMM chip did not fill the 64-bit bus?
The 32-bit 72-pin SO-DIMM chip
What 5 clock speeds were commonly used on early SDRAM systems?
66, 75, 83, 100, and 133 MHz
T or F, the SDRAM was tied to the system clock speed so its clock speed matched the frontside bus.
True
What is RDRAM?
Rambus Dynamic Random Access Memory
What is RIMM?
The letters of RIMM have no meaning. They were a name given to match the names SIMM and DIMM
What sizes did RIMMs come in?
184-pin for desktops
160-pin SO-RIMM for laptops
What were the speed ratings of RDRAM?
600 MHz, 700 MHz, 800 MHz, or 1066 MHz
Explain the dual-channel architecture of RDRAM?
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.
What is DDR SDRAM?
Double data rate SDRAM
What pin configurations did the DDR SDRAM come in?
Desktops: 184-pin DIMMS
Laptops: 200-pin SO-DIMM or 172-pin micro-DIMM
Describe how DDR sticks and chips are named.
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
How does DDR2 gain a speed advantage over DDR?
Clock doubling the input-output circuits on the chips and adding special buffers. This does not speed up the core RAM.
What pin configurations do DDR2 RAM use?
Desktop: 240-pin DIMM
Laptop: 200-pin SO-DIMM
What pin configuration does DDR3 use?
Desktop: 240-pin DIMM
Laptop: 204-pin SO-DIMM
What is SO-DIMM?
Small Outline Dual Inline Memory Module
How does DDR3 gain a speed advantage over DDR2?
It doubles the buffer from 4 bits to 8 bits
What does XMP refer to in relation to DDR3?
Extended Memory Profile; it enabled power users to overclock their RAM
What is triple-channel memory?
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.
What is a double-sided DIMM?
A RAM stick that has chips on both sides.
What does CL refer to in relation to RAM?
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
What is parity checking?
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.
What is error correction code (ECC)?
A form of error correction what identifies errors in bits of ram and repairs them on the fly.
What are signs that you might need more RAM?
- General system sluggishness
2. Excessive accessing of the HDD
What is a page file?
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
What is the recommended size of the page file?
1.5 times the amount of installed RAM
How does Windows determine which application to move to the page file?
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.
What is disk thrashing?
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.
What is ReadyBoost?
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
What is Serial Presence Detect (SPD)?
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.
What are the two types of parity errors?
Real and phantom
How do you recognize a real parity error?
It errors at the same location in memory each time.
How do you recognize a phantom memory error?
It errors at different places in memory each time
What is a nonmaskable interrupt (NMI)?
An error that occurs that cannot be ignored by your computer, resulting in the BSoD.
What methods can you use to test RAM?
- Purchase RAM testing hardware (expensive option)
- Replace potentially bad sticks of RAM with known good sticks of RAM
- Run a software test on the RAM
