Having exact same problem. Installed (clean install) yesterday the new 13.12 and the crossfire tab magicaly disapeared. Never happened with older drivers.
Noticed that the second device shows in catalyst control center as disabled...
Running dual 6950 in MSI P67a GD65 and core i5 2500k.
Edit: Allready tryed to disable ULPS and nothing
03:12 PM by