"So, you like NVIDIA and you've bought yourself a GTX 480; you're someone that doesn't mind splashing a bit of money around so you're thinking about a dedicated PhysX card. You're not going to spend GTX 470 or GTX 480 money on a dedicated PhysX card. Instead something like a second hand GTX 2XX series could be a goer.
The thing is, you might find that you want to stay with the GTX 400 series, so the perfect card could be here for you. The GTX 465 comes in at under $300 and offers some pretty good performance. What kind of performance under PhysX, though? Is adding the card as a PhysX card to an already highly powerful card going to make a difference? Well, to be honest, I'm not sure. But I intend to find out today while at the same time letting you find out, too."