From Gamespot, no less.

Ars had a quick write-up on it (just a few thoughts), and some of the comments left by people make me feel pretty confident about my computer's ability to run the game decently. Hell, one guy is running it at 1600x1200 and says its like playing a movie (1080p is 1920x1080) - believe he said his video card is a Radeon x1900 (DX9), no AA, although he doesn't mention his CPU or RAM total. Other people are getting good results on older machines provided the settings are turned down (including one guy on a 17" iMac (C2D 2ghz, 2g ram, x1600 video).

Sadly, everything's swamped (high demand, it seems), so I'm going to wait a little while (maybe Wednesday) before I attempt to download it. But I'm ready! Good grief, though - the demo is 2 gigs!