This guy got a bonner with the card:
This card is a huge improvement over the stock ATI card that came with my Mac Pro. Everything is faster. Safari and Finder load …Read moremuch faster. Iwork and Office 2008 are much snappier and more responsive. Noticeable improvement in scrolls in long Word 2008 docs. I run a 23" and a 20" display and this card handles both superbly. Text seems sharper. The entire effect is a substantially noticeable speed increase for all aspects of using the machine. I think the much ballyhooed barefeats scores are fairly meaningless in real world use. My experience indicates that this card is a great value and huge improvement, to heck with artificial benchmarks (yes I use aperture). In fact, the more I use this card, the more I am amazed that I put up with what is now shown to be very marginal performance from the stock ATI card. I highly recommend this card without reservation. PS -- I have noticed no additional noise after the card swap.
Pros: Huge improvement in speed of all applications in day to day use. Big improvement in game speed. Better text rendering.
Cons: None (although you do have to connect a supplemental power cord when you install and that requires a little care, but is not difficult.
I would buy another fast ati card if it worked with all 3 os's, give Apple a year, and maybe it will work with next years mac pro