so... I read more...
first
what the PPU /physics is? same software calculation to obtain same visual effects like: deformation, explosions, impact and ~ all the real world law of physics. (that can be used in a game/simulation)
2) in one normal system this software calculation are the CPU job, because there are not actually have a specific hardware device. So in this case the need is to have a specific hardware device that can handle this kind of calculation. So from that the people from ageia, make the PPU.
So far all are ok, but .... not all the game/application use same software to have physics in game/application. that because, there are many software/game developers. the developers can use different physics engine, like havok, ageia, or any from the open source. Also the this physics engine can work a hardware device or with out a hardware device, in that case the CPU take the job.
ok, so the new driver from nvidia come and take the job from the CPU(in normal pc) or PPU (in the pc with ageia card) and execute the job in the GPU. And with this driver we have a new working concept.
3) the vantaje have test for CPU, GPU and physics. the "problem" is that the physic was designed to be run in CPU with or without PPU(ageia card). but this test is actually done it by GPU. The result is a logical (I think is logical) optimization for the all system (the pc). But the test are totally NOT REAL, is simple don't test the physics capability of the CPU (with/without PPU), It test the physics capability of the GPU. All the test results are not comparable, it's like you compare an apple with an chicken egg.
And an idea, because the actual GPU (ati and nvidia) are very solid, I believe that the ageia engine (like the havok engine) can be run even in a non nvidia card
, but I know is not opensource