It would be ridiculous to buy a GTX 480 as a PhysX only card for your Radeon setup. The high cost of the model combined with the fact that the whole setup is done with a hack makes it a real pain. If on the other hand NVIDIA gave ATI users the chance to officially support a standalone NVIDIA card as a PhysX one with their ATI option, then we could recommend the setup. Mind you, we would probably opt for something not quite as expensive; a GTX 470 or hopefully one of the newer mid-range GTX 400 series cards that are due out mid-year.
The bottom line, however, is that if you really want PhysX you need to know that unofficially you're not pigeonholed into an NVIDIA only option when it comes to your primary graphics card. If you're on something like the HD 5870 and wish you could make use of PhysX, picking up a second hand GTX 275 or GTX 285 could be a nice little option.
Why NVIDIA don't just give people the ability to use their card as a standalone PhysX card with an ATI offering is beyond me; the issue with PhysX is that it's not a big enough selling point to most people to buy an NVIDIA card at a higher price when compared to an ATI one. On the other hand, if they offered it officially, picking up one of the mid range GTX 400 series cards due out in the middle of this year could be a nice little option for HD 5870 and HD 5970 users.
This would also give companies more of a reason to offer PhysX support. With NVIDIA market share at its worst in a long time, when it comes to performance gaming why work hard on implementing technology that is only going to be used by a limited amount of people?
PhysX is a cool little piece of technology; to some it's having flappy pieces of paper moving around the screen, while to others it adds another dimension to their gaming experience.
While we wouldn't suggest that you go as wild on a setup as the one we tested today, it's good knowing that the setup is working on the latest NVIDIA offerings thanks to the Hybrid PhysX mod which we mentioned in our news recently here.
While certainly not for everyone, if you're looking at getting your PhysX fix on your ATI offering, it can be done; and with relatively no pain.