Sean Costello said:
are they both the same DDR rating and just have different latencies? If that is the case then the lower would be quicker by milliseconds but that can add up. If the cas9 one has higher ddr rating then I dont think there would be any noticable difference.
They are DDR3
I think you meant nano-seconds (billionths of a second) difference...not milli-seconds, unless you're talking about the final result of some specific
benchmark like Prime95 running a specific scenario and number of iterations.
Unfortunately, the final performance difference is not linear. Memory management doesn't work that way, so I can't just assume that because a memory stick has a different parameter means I'll see a 1:1 percentage difference in end peformance. (e.g. CAS7 does not provide 22% faster system performance than CAS9...it might end up being less than 5% all things considered and that would mean it wouldn't be worth the added cost to me).
One real-world example,
I've got DDR3 9-9-9-24 and DDR3 8-8-8-24
I can find virtually no effective difference in the execution times of various programs or program operations between using the two sets of RAM, including when I toss-in substantial multi-tasking. Yes, benchmarks show some difference, but it does not translate to any tangible difference for normal program operations. (mobo=GA880GMA-UD2H, AMD Phenom II X4, SATA 6Gb/s 7200rpm drive).
Thus, I can't see that CAS7 7-8-7-20 would make that much tangible difference in the real-world
The problem I face is that I don't have any CAS7 (whatever sub-timing parms) RAM to compare. All my current DDR3 memory is either CAS9 9-9-9-24 or CAS8 8-8-8-24.