Switching PCI-e ports might be a good idea. If you have GPU-z installed, is it reading your card correctly? Might be a dying GPU?
When you say you have "tried loads of drivers" how did you install CCC? Just over the old version? Uninstalled and then re-installed? Or did you uninstall, restart in safe mode and use a program like drive sweeper to erase any lingering files left over?