At last, Stanford University has released a beta version of the GPU2 Folding@home client for Nvidia graphics cards. You can grab the client from this post on the official FAH forums, although Stanford's Adam Beberg suggests users closely read the FAQ page to familiarize themselves with the software first.
To run the Nvidia GPU2 client 6.12 beta 6, you'll need one CUDA-capable graphics card—typically anything in the GeForce 8, GeForce 9, or GeForce GTX 200 series—and a 32-bit version of Windows Vista or Windows XP (no 64-bit, Linux, or SLI support yet). Stanford mandates the use of a CUDA-capable ForceWare driver (version 174.55 or later), which Nvidia offers on this page.
This being a beta release, Stanford also warns that it expects to find "bugs, flaws, problems, etc," and it recommends that users back up their hard drives and avoid running the client on "any machine which cannot tolerate even the slightest instability or problems."
Those who give the client a try anyway will find something similar to the PlayStation 3 client, with a real-time visualization system that shows simulated proteins. Gamers may not have to worry about performance problems, either. The FAQ explains, "Playing videos and playing games either have no effect on the action of the GPU client other than a slow-down in processing, or cause a temporary suspension of folding. The new client will automatically back off whenever an application requests exclusive DirectX mode."