I was having the same problem with xfire running version 12.6 but I cleaned them out in safe mode ( uninstalled and used driver sweeper ) reinstalled 12.8 and my xfire problems seem to be gone but am only getting 60fps during a fight ( which is better than 2fps in a fight ) and my normal just running around is still 110fps. I am using 2x6970
Update Sept 27
Seems the bugs are back after having the computer off overnight. no Idea why it seemed to work after a driver update, but I don't want to have to do this every time I want to play the game. Please fix this ASAP so we can all enjoy the game.