Hi there, I just purchased a 5770 to replace the old 7300gt in my 2006 mac pro 2x2.66 ghz with 8gigs of ram, and I have to say, WOW! This machine now runs lions seamlessly with all quartz animations fluent. On top of that, Final cut X now runs faster than ever on this machine, and my gaming in COD went from "all low" to "all on Ultra", including x4 AA. Basically, with this 5 year old machine, I can now play cod 4 at 1920x1200 with everything cranked up at around 40 fps. Cinebench gives me a score of 27 for the card under lion, and uh.. I think I pretty much said it all. IF you have any other questions or benchmark requests, feel free to ask!