My experience in 3D Mathematica graphics, is that it is also slow. I stopped doing 3D physics simulations in Manipulate as it can become too slow and not really usable. I once spent 2 months making 3D physics simulation (Symmetric top gyroscope) in Manipulate, and could not making it fast enough to use, even though the 3D graphics look nice, it was not really usable as it is just too slow.
I can't answer the question if it uses graphics card or not, just to mention that I had the same issue with 3D in Mathematica and others also. Here are some links
how-to-make-graphics3d-with-multiple-lighting-sources-being-rendered-faster
How to improve performance of Graphics3D rendering with Dynamics
May be someone from WRI can answer this problem one day. Mathematica 3D graphics look really nice and very well designed. But if they are slow to render, then they will not be too useful for doing simulation.
I am on windows 7, 64 bit. Fast intel CPU, 16 GB Ram, NVidia graphics card.
