Also curious as to how the 6870 works with the x58a-ud3r and mountain lion. What have you done as far as install, kexts, plist, ect? And do all ports work?
I have a system I just upgraded to lion. I use it for audio and didn't expect avid to support 10.8 anytime soon. Well it looks like it will be sooner rather than later so I'm considering moving on up to mountain lion. Fwiw I believe the card I have is an actual amd card. I bought it used off eBay and it doesn't have any other brand names on it. Also I just upgraded the card from a 9500gt as I thought it was dying. Turned out to be my monitor. Anywho I have a way better graphics card. Just want to get it working 100%.