I've only experienced 1 problem with the card, which is explained in this thread.

http://forums.worldofwarcraft.com/th...96482353&sid=1

I doubt that's your problem, tho and we have almost identical systems .. except for the harddrives. What happens if you turn AI off in the settings?

My card never gets above 70 degrees, full load - so that's quite interesting aswell (auto control).