What I don't get is how can hardware be optimized for graphics? Are graphical functions different on the hardware level to non-graphical functions?
3D graphics GPUs are massively parallel, with dozens/hundreds of cores running very limited instruction sets, which are highly suitable for vector calculations but not so much general computing. That said, CPUs and GPUs seem to be converging, so years from now I wouldn't be surprised if they merge. Then we can go back to software rendering. (Which sounds bad initially when you're used to GPUs, but in reality not only would speed not be an issue, but it would allow you to ditch OpenGL/Direct3D with their attendant limitations, driver problems, etc. and just do whatever you want. That's right: Mac versions of games will finally perform the same as Windows, and be a lot easier to port.)
--Eric