Just wanted to say that I have the same graphics card and the exact same problems with it (Gnome 3 even with all the patches and everything would still "restart" once per hour at least), so seriously if you are interested in running Linux avoid AMD.
... if in the next 6 months the situation doesn't get any better I feel I am going to physically destroy the GPU with a hammer, send the pic to AMD and buy a nvidia before the need for a hardware upgrade even shows up. The fact that it has drivers problems even under windows doesn't help making AMD's case.
TBH I also gave up about a month and a half ago it could have changed recently but I doubt it.
Waay to slow for gaming (I tried HoN and NVN) also WebGL was really slow (software rendering kind slow), since this is a thread about games I think this use case is required - I didn't try the OSS drivers in ~6 months so it could have changed. But Gnome/desktop was really stable so if you only need desktop apps it does work.