I had the same problem when running Guild Wars 2. I updated drivers but it didn’t go away. Changing the rendering sampling to subsample (blurry graphics) or super (very low FPS) worked but wasn’t the best fix. I downloaded the newest Catalyst application profiles from AMD:
http://sites.amd.com/us/game/downloads/pages/crossfirex-app-profiles.aspx
and now everything works perfectly. Might fix the problem your having.