I read it was going to be PCI, as others mentioned here. I do agree the PCI express bus probably would be a better choice, but prices would probably be less for plain PCI. Besides, it seems to work just fine like this, right? I mean, take a PCI version of the fx5x00 graphics cards. They're quite capable when you consider how limited the PCI bus is, right? That's about all this card is, but rather than dedicating it to graphics, it's to physics. Heh, looking at that card, it IS just a graphics card. Seems to have the RAM there, and even requires the extra power that most do
Oh yeah, for those who couldn't see the pic above...
http://www.importjdm.com/shipped/physx.JPG