They should both run in the 08 pro. Depending on your price limit I would go with the gtx680, its much much better with games.Do both of these run fine in an early 2008 Mac Pro? Sapphire does not have the 2008 model listed. After buying a new 3.06 12 core, I gave my son the 2008.
Thanks for the tip MacVidCards. I am waiting for my friend's decision if he will sell his other GTX680 as he has 2 of these. Will also check out eBay.you can flash one yourself
or go to Ebay, lots for sale there
you can even get 4GB versions on Ebay
One really brilliant seller has GTX770 cards already.