Well, resolution matters. If you're going to be playing Crysis on at 1200x, than a 5870 is complete overkill. Anything 1920x (max details, AA, AF, etc) and over you'll want the 5870 most likely. If you can afford it, I'd go with the 5870. If you want a setup that will still get the job done and $100 cheaper, than the 2x5770's are better for you.