He can actually use both, and should if possible.
NVDA is a better company with better products, imo, but that ATI card is a better model. However, ATI does not have Physx, because it is NVDA only. There is a program that lets you use the NVDA for the physx part and then use your ATI for everything else. I don't recall what the program was, I just read about it on the NVDA stock forum.