I might be completely wrong here.. but i was looking at how the ram works with its latency and how you can figure out how fast your ram will run at a certain mhz with a certain cas latency. now when i opened up cpu-z it shows that my ocz pc26400 ram will run at 400 mhz with a cas of 5 which comes out to 12.5 ns and at 333 mhz a cas of 4 and that comes out to 12 ns and at 266 mhz with a cas of 3 wich comes out to 11.27 ns... so now if i were to underclock that ram wouldn't it run faster??? or have i read to much lately and im confusedddd..
If you really want to know how much difference it makes, you can always use a benchmark to compare. Personally, I don't really care about RAM speed that much, because the difference is negligible, unless you are overclocking.
Generally, latency don't make much of a difference these days. But like Chai said, you can use a benchmark to be sure which is faster for you - lower latency or higher frequency.