I've just benched the leaked 171.16 betas using the Crysis benchmark utility and I got 5 extra FPS! My settings were all on high apart from Textures, object quality and shaders which were on medium, I also had 2xAA. Normally I'd get an 'average' of 33fps on the gpu benchmark. This new beta gave me an average of 38.5fps!
You can link through here:
NVIDIA Forums -> Forceware 171.16 Vista 32 and XP 32 is out! (XP is there too but not sure if they're giving the same improvement.
I've also read that a further driver, 173.61, gives even better results but as of yet no link has been given or they've not been leaked yet. The article is here:
VR-Zone : Technology Beats - NVIDIA Forceware Vista Beta Drivers Preview