To be honest, I can't really tell a difference between CAS 8 to CAS 7. CAS9 to CAS 7 might, just might, make a noticable difference on a really memory intensive program. I think for whatever reason ever since memory controllers moved to the CPU, latency has become less of an issue. If you benchmark, and look at the throughput, latency makes a difference. When you compare that to overall system/gaming performance, then you have a hard time trying to see the difference. Figure also, not every application is memory bandwidth intensive. I have really, really, loosened up timings when troubleshooting systems, and I do notice a difference on old SDR and DDR systems a lot more than modern stuff.
All that being said, I still go for the best (fastest/lowest latency/lowest voltage) memory that fits the budget. I just like to have headroom with my components. Get memory rated to run with at least a synchronous "bus" speed with your CPU. If you are going to overclock by bumping FSB/BCLK, make sure your RAM can run at those speeds as well.
Edited by dpunisher, 04 July 2011 - 12:18 PM.
I am a retired Ford tech. Next to Fords, any computer is a piece of cake. (The cake, its not a lie)
3770K @4.5, Corsair H100, GTX780, 16gig Samsung, Obsidian 700 (yes there is a 700)