I've been having a, I believe, driver problem which occurs after long gaming sessions on games like Battlefield, Farcry 3 and metro, if that helps at all. The screen randomly splits off into two pieces so the centre would become the edge and stuff like that. I have tried reinstalling drivers and my GPU temperatures rarely go above 70 because I always have the fan ramped up on it.
Here's a picture of what happens, sorry for the bad quality they're taken on my phone.
Try installing older drivers. I had to install the Nvidia 320.14 drivers because 320.18 was causing random black outs on my screen. I don't know about AMD drivers, but try an older Beta release, or something.
My friend Andrew, who also runs a 2500k and a 6870 has the exact same issue. I don;t have any solutions for you but I wonder if it has something to do with those two parts? Seems very strange to me.