So I just got a hd 6990 very good price lower than 200 and it was in mint condition. And it having a lot of performance issues. I have graphical glitches and fps stays around 20 fps the temps are normal around 85c. And I think it a driver issues because I just put me it back in today and it was working like it was suppose to do and as soon as I restarted it it started to have the issues again, anyone know a stable driver version or have any idea what causing it.