It's finally here folks and the good news for the "Boot Screens? We don't need no stinking boot screens" crowd is that AMD drivers are present for many cards, at least 3 that I test from 7xxx series all work fine in prelim testing. Note that GLViewer crashes when I try to run the newer OpenGl tests so that isn't a good sign. Cards tested thus far include an HIS 7970, a UEFI PCS MYST 7870, and an el cheapo Gigabyte 7770. All 3 cards were able to run a 24" and 27" LED Apple display simultaneously on the MDP ports. I would expect them to run 4 total displays at least, but have not tested the other ports. So, yes, you can more than likely pop any card from those models in your Mac Pro in 10.8.3 and have a working card. The announcement of Mac 7950 seems to make this likely to keep working. This was tested in a 3,1 but I will also be trying in 4,1/5,1. On the bad news side, the 6950 is still a KP star. Netkas was kind enough to write an EFI so you get a nifty boot screen, followed by the Curtain of Grey Death. (in several languages) Not sure why AMD/Appple gave us a taste of these cards working, then killed them. Anyhow, time to try some 7xxx cards in your Mac Pro.