I have found the Forceware drivers 6.86 for the Nforce 4 boards cause a huge problem in game causing the game to seriously drop in framerate to Under 10FPS.
I downloaded these drivers from Nvidias Website only a few weeks ago and have since noticed that it looks like Nvidia have rolled back the driver to 6.69 (at least on Windows x64)
As im using X64 i have no idea if this effects 32bit users but i thought you should know.
Warning Nforce 4 Drivers 6.86
Hg80