I have an I5-750 with Geforce 570GTX, the game is playable at 1920x1080 with everything on, but framerate constantly drop at somes place so the car seems to slow down a bit sometimes and make things harder to be played.

It must have a patch to correct this.  Graphics are great, but now enough to be so heavy.  For now, I drop the resolution to 1280x720 (yes like the Xbox :?) so the game is now much more enjoyable to play.

Give it a try !