It ain't gonna happen.
I'm in agreement with the THG article on the topic that when ya turn on PhysX in a game that is so equipped, ya ain't gonna turn it off if ya system can handle it. The eye candy simply adds a lot tot he game experience. A dedicated PhysX card makes it handle it.
Hmm, only game I have that really uses physx is mafia 2 so I'm probably not gonna do anything