Well, i put the EFI version of 6950/70 in and it KPs in 10.8.3.
This card has ping ponged between working and not working from one OS update to another.
So until the 7xxx series work in two OS updates in a row, I wouldn't get too excited.
On the PLUS side, the 7770 does work.
the nvidia 680 does not work perfectly though - no boot screens :/
I put an nvidia 570 in my mac pro, replacing the 5770 - was hoping it was going to make a HUGE difference!!! the reality was a lot less!!! yes it was faster than the 5770 when gaming, but not really noticeably... I only ever really play lotro though, and thats native under mac os now made such a little difference, I actually put that back in my PC and put the 5770 back in the mac!!
how are we looking re the power draw on the 7970? I know it's a bit more than the nvidia 680, but it's not *much* more... the official specs say one 8 pin and one 6 pin supply
but it really made no difference when actually playing, think i had it at standard settings, at 1920x1200 res.
So... this gets a front-page news story, but the fact the GeForce GTX 680 started working with Mountain Lion goes unnoticed? I sense a bit of bias here, but I guess there are plenty of AMD fans out there that would care about this.
Edit: Note that the 7970 has an 8-pin power connector, so suffers from the same issues as the GTX 580 in terms of requiring an external power supply.