TheTechLounge posted an article on ATI HD 2900 XT Vista Performance

Hardware like video cards, especially high-end video cards, often fall under the purview of the Enthusiast. An enthusiast is a computing hobbyist with a kind of hardware pioneer's mindset. Never quite satisfied with where he or she is, enthusiasts tweak and modify, often risking and sometimes obliterating good hardware in attempts to find its limits. But there's often one territory that enthusiasts avoid: new operating systems. This makes sense when you think of an operating system as the set of tools used to trailblaze hardware. How would you go digging when your shovel has a hole through it? ATI's current flagship, the HD 2900 XT, runs about the same as NVIDIAs 8800GTS 640MB on computers using Windows XP. But that's patently irrelevant for Vista users. Here are the numbers from a side-to-side comparison: the pioneers of operating systems read on.

ATI HD 2900 XT Vista Performance