DiRT 2 Gameplay Performance and Image Quality
 

No, the only advantages that we see that make a real difference are 64-bit HDR, HDAO, and the improved shadow quality. They do look nice, and it is easy to tell a difference during normal gameplay. But does that justify the cost of buying a new video card? Value, of course, is in the eye of the consumer, but we wouldn’t place our money on it quite yet, at least for this game. Certainly not in what may be the weakest economy in decades.

http://www.hardocp.com/article/2009/..._image_quality