Nvidia, and ATI both released new beta drivers pretty much just for this game that make it faster, and more stable. Of course if your graphics card doesn't support shader model 3.0 it's not going to look right at all anyway.
I got the demo, but when I try to run it nothing happens. My cursor changes to the loading cursor for a couple seconds, then no game, no errors, no anything. I know my computer is better than the minimum requirements.