Understanding memory timings ?

Jim_b0b

Novice Member
Could anyone help me understand memory timings ?

ie. is 4-4-4-12 better than 5-5-5-12, and is 4-4-4-12 better than 4-4-4-18 ?

Thanks.
 

overkill

Distinguished Member
The lower timings, the faster the memory is. A module with 4-4-4-12 is faster than one that is 5-5-5-12. However, if the bus speed on the former is 667mhz as opposed to 800mz in the latter, well that's reduced any impact the timings make.

With DDR ram the timings were critical for gaming systems. Corsair ram for example went as low as 2-2-2-11, but it was mind numbingly expensive and only the best systems could make it really work for them.

With DDR2 the timings are nowhere near as critical.

Tbh, whereas with DDR I used to really watch the timings, with DDR2 I just go for which modules will work best with the system, and value for money. As long as the modules are made by a good quality manufacturer all will be well.

I wouldn't get too het up over it.
 

EndlessWaves

Distinguished Member
With DDR ram the timings were critical for gaming systems. Corsair ram for example went as low as 2-2-2-11, but it was mind numbingly expensive and only the best systems could make it really work for them.
2-2-2-5 for DDR, and even with that it didn't make that much difference (I think it was 5% at most in certain usages).

They refer to the number of clock cycles it takes to perform certain operations in the memory.
 

overkill

Distinguished Member
2-2-2-5 for DDR, and even with that it didn't make that much difference (I think it was 5% at most in certain usages).

They refer to the number of clock cycles it takes to perform certain operations in the memory.
Apologies. I just checked and it was 2-2-2-5. I should have known, I just sold a pair! :rolleyes:

CAS is short for "Column Address Strobe"

First off, the chip set accesses the ROW of the memory matrix by putting an address on the memory's address pins and activating the RAS signal. Then, we have to wait a few clock cycles (known as RAS-to-CAS Delay). Then, the column address is put on the address pins, and the CAS signal is activated, to access the correct COLUMN of the memory matrix. Then, we wait a few
clock cycles -- this is known as CAS latency -- and then the data appears on the pins of the RAM.*

*Pinched from Corsair.
 

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