One core of a core duo processor can be used to handle the 3D stuff (or both cores it doesn't matter ), but will not do hardware accelerated graphics, it's still a cpu rendering graphics wich means crappy performance.

One thing is sure, we need 3d acceleration in our carputers, Im working on a 3D front end, would be nice to be able to use shaders and all the stuff, can you imagine a glass looking skin?