I was having some problems with my videocard and I came across these two tweak guides which I found very helpful and informative. I don’t know if anyone has checked them out, but I highly suggest that you do to improve your videocard performance and stability.
TweakGuides.com - ATI Catalyst Tweak Guide TweakGuides.com - Nvidia Forceware Tweak Guide
The same guy has a number of tweak guides for windows and popular games such as Crysis Warhead and a lot more. I highly recommend that you check the full site out.
TweakGuides.com