How to read RAM latencies?

CAS Latency, the first RAM timing setting (number 5) is the most important. The frst 4 timings you listed are the important timings. The lower the timing, the more responsive the RAM becomes within the system. The higher the timing number the more 'flexible' or loose the RAM's timings become when communicating with the processor for example. This holds true for all the RAM timings including the minor settings. A simple answer to your question, What do those numbers mean? The numbers are the four most important RAM timings. I think since you are asking the question you are asking, I suspect you could not tell the difference should you buy CAS 5 or CAS 4 rated RAM. I think experienced users definately experience the difference.


Aug 17, 2007
what do you mean the more flexible / loose? What is CAS latency?

Thanks for your explanation, it makes things a bit clearer. Clearly the lower the more responsive, the better.

Can you also tell me what each one means?


Mar 25, 2007

CAS latency is the time that elapses between the memory controller telling the memory module to access a particular column in the current row, and the data from that column being read from the module's output pins.

so yea, you pretty much have to have a general understanding of how RAM works in the first place in order to understand what the timings mean and how they work.

Oh also just thought i'de throw this in there: the ram you chose in your original post has somewhat high latencies, 4-4-4-12 would be better, however the actual difference you would see would be minimal. plus, if you intend on overclocking, you could just manually adjust the latencies.