“Anandtech”:http://www.anandtech.com/video/showdoc.aspx?i=2751 reviews a physics acceleration card. This takes the physics modeling in games, (you know, shoot a bullet, hit a guy and how does he fall?) and puts a dedicated processor in to do that.
It’s for the ultimate gaming geeks and requires specialized games to take advantage. The just shipping Ghost Recon Advanced Warfighter does that. Unfortuantely, for that game, installing the card actually slows down performance. The quality of the explosions are higher, but the game plays slower with the added realism. The main competition as usual with these kinds of processors is multithreading and having dual core processors. So it is another case of special purpose vs. general purpose. In the case of graphics, the special purpose stuff won. Here, the jury is still out.