I forget where it was at......some other forums I think, but this one guy ran like every major benchmark there is on his ram at cas 1.5, 2, and 2.5. Guess what? It didn't do a d*mn thing.
1.5 was actually a few points/fps lower in all of the tests except for one (still only a few points/fps better).
I could care less about the timings, you'll get so much more from pure Mhz then begging for an extra nanosecond. I've tried it myself. Plus, like Maxvla said, he could have cas2 at 145 or cas 2.5 at 196........I'll take the (almost) DDR400, thank you.