Chapter 4 starting at page 147 Flashcards
Every type of RAM stick comes in either single sided or double sided. T or F.
True
Some motherboards cannot used double sided RAM sticks. T or F
True
The delay in RAM’s is called CL17 or CL19. What does this acronym stand for? Which is faster?
column array strobe (CAS) latency. CL17 has a lower latency, which means it responds faster than the CL19.
CL17 - what does the CL refer to?
CL- clock cycle delays. CL17 means the memory delays 17 clock cycles before delivering the requested data; 19 means 19 clock cycles delay.
What will happen if you put a high-latency stick in a motherboard set up for a low-latency stick?
your system will become unstable or not work at all.
What is the purpose of parity RAM?
Parity RAM stores an extra bit of data, called the parity bit, that the MCC uses to verify whether the data is correct. It is not perfect, and doesn’t always catch the error.
PC’s today use ECC RAM. What does that stand for and what does it do? What are the limitations?
ECC - error correction code RAM.
ECC detects and corrects any time a single bit is flipped.
Limitations are that only a single bit can be corrected, not a double bit error. Also, ECC RAM is always slower than non-ECC RAM.
ECC DRAM comes in every DIMM package type, but has some odd pin numbers for DDR2, DDR3 or DDR4 sticks. What are the odd pin/bit numbers?
DDRx come in 240 pin, 72 bit versions.
SODIMM come in 200 pin, 72 bit format
The extra 8 bits beyond the 64 bit data stream are for the ECC.
Some manufacturers use a different name for ECC. What is it?
error checking and correction. - same thing, different name.
What is the purpose of registered RAM or buffered RAM?
Both terms refer to a small register installed on some memory modules to act as a buffer between the DIMM and the memory controller. This circuitry helps compensate for electrical problems that crop up in systems with lots of memory modules, such as servers.
A motherboard can use either buffered or unbuffered RAM. T or F
False, it can only use one. Unbuffered is normally used in typical consumer products.
What is the most important upgrade that can be made to improve system performance?
Adding more RAM. It will improve overall system performance, processing speed, and stability.
To get the desired results from a RAM upgrade, you must do 3 things. What are they?
- determine if insufficient RAM is the cause of system problems.
- you need to pick the proper RAM for the system
- you must use good installation practices using static bags, and strict ESD handling procedures
Two symptoms point to the need for RAM, which are?
general system sluggishness and excessive hard drive accessing.
