Sandra unbuffered score better with CAS 2.5 vs 2

Title basically says it all. I'm running 4x256 (please don't laugh) Mushkin 3500 black lvl2 @ 240fsb. With 2-6-2-2 timings I get 3350 unbuffered. At 2.5-6-2-2 I get 3440.

The scores were very close in 3dmark01 by about 20 points.

Should I get more comparisons? Is CAS 2.5 possibly better than CAS 2.0 in my system?

The differance is slight (either way) to none for CAS Latency while RAS-to-CAS remains at 2 on i875/i865 chipset boards. Performance differance of 20 points (1 FPS increase in High Detail - 2 FPS in Low Detail) in 3DMark01 is unnoticeable and is most likely caused by variations in each run. As long as your memory retains a tRCD of 2, performance shouldn't suffer.

does that mean he should go with the 2.5 timings and try to push further if his ram is the limiting factor? Or just stick witht he 2?

Typically tRCD is the limiting factor.
If 2,5-2-2-6 allows you higher FSB without loosing memory performance then go for it. But don't expect that it will go
much higher.

BTW: That is a stunning unbuffered score for FSB 240.
Good luck!