I'm actually surprised people are having problems running this. My home PC isn't anything amazing but I'm able to run it 1900x1200 with all the highest settings and don't notice any problems.
The real odd thing is the settings defaulted most everything to normal and when I changed everything to high I couldn't even notice a difference. I played this afternoon on my work PC that should still have everything on normal and I didn't notice any differences at all (in fact, it ran a little slower but that was problabmy because I had many other memory hog programs running).