The State of Hardware Accelerated Physics
 

If you believe the more tabloid-oriented hardware news sites, 16 months ago you would have thought that ATI and NVIDIA were at an all out war. Harsh phrases were flung, benchmarks were beat to death, and both sides plotted for motherboards with a third x16 PCIe slot in order to have a GPU dedicated to physics. Yes, 2006 was sure an exciting time for GPU-accelerated physics, and then the party came to a grinding halt. Over in the Ageia camp, 2005 saw them kick off the whole subject of hardware accelerated physics with their announcement of plans to develop the PhysX hardware. 2006 saw the launch of that hardware, and while it had initial promise there was a failure to follow through with games that meaningfully used the hardware. Much like with the GPU camp, Ageia has been keeping a low profile so far this year.

http://www.anandtech.com/video/showdoc.aspx?i=3048