I'm a bit confused about RAM speeds, latency, and transfer rates.
From what i can make out so far, RAM is rated on it's clock speed and latency. There are a few different latency measurements (the string of 4 numbers, eg, 5-5-5-18), however the only really important number is the last one which measures the overall latency between the access of data between two "random" areas of memory (please correct me if I'm wrong).
My question is this:
how would you calculate the actual RAM latency (ie, in nanoseconds). Is it the tRAS divided by the RAM clock speed or is it the tRAS divided by the processor speed (which doesn't sound right to me, processor shouldn't affect the RAM access like that) or is it something totally different?
Also, how does duel channel and triple channel affect the RAM latency (from what i can gather, it doesn't, it just affects bandwidth) and how exactly does it work? Is it just basically something like striping with RAID for hard drives?
Lastly, is there any difference between access speeds for reading and writing? Does writing take longer and, if so, how is that reflected in the latency timings, or even if it is.