He tried to implement the physics and said that to his horror he learned that ATI and Nvidia "cosmetically" affects the physics. The developer added that only Ageia can handle game play physics. The same level of physics quality cannot be achieved using GPU physics, and even high end cards such as X1900 XT or 7900 GT cannot handle it.This will likely change with DirectX 10 but for the time being an AGEIA PhysX cards is much better. More details over here.
If you want to use 3D particle water spray or wave ripples, you need Physics do to it properly. This is a real shocker as ATI and Nvidia did a lot of PR about how well they can handle physics.
ATI/NVIDIA Physics not as good as AGEIA's
Posted on Wednesday, July 05 2006 @ 3:30 CEST by Thomas De Maesschalck
The Inquirer heard from an anonymous game developer that ATI's and NVIDIA(s on GPU Physics isn't even close to what you can do with an AGEIA Physics card: