The jolly green giants Nvidia recently blocked PhysX support when an ATI board is included in a system build for graphics rendering.
The latest version of the PhysX system software also prevents physics processing cards from working if any other card apart from Nvidia is being used. Many people have been debating whether Nvidia are breaking some ethical conduct by forcing these rules on the end user.
Fear ye not, because a guy going by the name of GenL on the NGO forums appears to have patched Nvidia’s ‘disable if ATI card is present’ PhysX code.
It is still a work in progress but you can try it for yourself over here