I've just updated to 10.6.7 and my 5770 in a 1,1 2.66 Mac pro is behaving similar to when I first put the card in without the proper drivers installed. Specifically windows don't move smoothly around but judder around. On another point, I've also noticed that since upgrading to 10.6.7 on both my Mac Pro and Mac book pro, both now take significantly longer to boot up. I don't trust Apple as far as I could fQ£@%ing kick Mr Jobs so I suspect this has been done for no other reason than to make the expected (at least I'm expecting) longer boot up time of Lion more acceptable. EDIT: Thinking about it, perhaps the graphics card problem is intensional for the same reason - to make Lion feel good (perhaps I'm just in a bad mood!). Would be great though if someone could throw some light on the graphics card problem.