3.3 CQ

Question 1

What is the transfer rate of DDR4-2133?

A. 17,066 MB/s

B. 19,200 MB/s

C. 21,333 MB/s

D. 25,600 MB/s

Answer 1

A. The transfer rate of DDR4-2133 is 17,066 MB/s. It is also known as PC4-17000. 19,200 MB/s is the speed of DDR4-2400 (PC4-19200). 21,333 MB/s is the speed of DDR4-2666 (PC4-21333). 25,600 MB/s is the speed of DDR4-3200 (PC4-25600).

Question 2

How many pins are on a DDR3 memory module?

A. 288

B. 184

C. 240

D. 200

Answer 2

C. DDR3 is a 240-pin architecture. 288-pin is DDR4, 184-pin is the first version of DDR (DDR1), and you can find 200-pin architectures in laptops; they are known as SODIMMs. To review, Table 10.2 shows the pin configurations for PC-based DDR1 through DDR4.

Table 10.2 Comparison of DDR Pinouts

DDR Standard
Number of Pins
DDR1 - 184 pins
DDR2 - 240 pins
DDR3 - 240 pins
DDR4 - 288 pins

Question 3

Which of the following allows for a 256-bit-wide bus?

A. ECC

B. Quad-channel

C. Parity

D. DDR2

Answer 3

B. The quad-channel memory architecture can allow for a 256-bit-wide bus (64-bit per channel). However, this will only be the case if all four channels have memory installed to them. ECC stands for error correction code, which can detect and correct errors in RAM. Parity is when the RAM stores an extra bit used for error detection. DDR2 is a type of DRAM that, for the most part, was used in either single-channel or dual-channel environments.