i've been reading the codemasters forum for this game, and there is something very wrong with it, and people here are noticing it too:
Some users, even with top shelf GPU's and CPU's, are seeing piss-poor performance. It's not a cpu problem, as people w/ c2d's and c2q's are both seeing the issue and not seeing the issue. *Some* people with 8800GTX's in SLI are seeing the issue, some with just 8800GTX's are seeing the issue, and some aren't, etc etc for just about every decent video card from the last year or so. The game runs at about 1/2 the fps for *some* people, and from the multitude of threads ive read on it, I can't see a pattern at all.
It doesn't depend on cpu or cpu-overclock, gpu or gpu overclock (of course if you have a 7600gt or lower you wouldn't know if you were affected anyways
), game settings (even on all LOW/OFF at 640x480 on 8800gtx's the game maxes out at 40fps for some), sound card or in-game sound driver, etc.
This is not about the performance with multi-car races, btw. This is a very real problem, because my 6800Ultra 256MB agp runs the single-car races better than my 7950GT 512MB :O That simply should not be.
The 1.1 patch does nothing for this issue.
Also, just discovered that codemasters are deleting the threads on their forum where users are trying to figure out the pattern of hardware causing this. Sigh.