Can vista be reducing my framerate?

[#ELMO#]

Does anyone know if vista can ruduce framerates in gaming, as i can run the new unreal on full settings and it runs perfectly smooth, but on WoW i have to turn loads of settings off/down to get a decent framerate :O, but on my old XP laptop(Pentium 4, 1 GB ram, Go 6600 256mb,) i have the settings to exactly the same as i have to have on my new pc (spec in sig) to get a decent framerate,and get the same frates rates on both almost.as if my laptop is performing basically the same as me new PC does if you see what i mean?

Or could there be another problems somewere? iam debating weather going back to XP will be good idear anyways :P

Thanks

ELMO

[#ELMO#]

Ok been reading up on vista *shudder* and i have seen lots of people claiming they have tested both OS on the same computers and it can drop the framerates but 20-30 I honestly belive this
So basically ive answered my own question, sorry i should of maybe read up on this first