One card is XFX and the other is Sapphire. The cards both came from the factory already overclocked.
The sapphire card was clocked to 870 Mhz Core clock and 950 Mhz mem clock. And the xfx card at 860 core and 1050 mem.
I have to clock both down to 840 core and 870 mem or else they give me bsod after ten to thirty minutes of the following games:
Just Cause 2
Need for Speed (2010 or 2011 or whatever the new one is)
and occasionally during other games.
Both cards barely get above 80C after an hour on Furmark, and i have never had them BSOD during Furmark at the higher clock speeds, only during gameplay. Which makes me think dx may be to blame, but that doesnt make sense because JC2 is directx 11, Skyrim is DX10 and need for speed is (i think) dx9
I have a 750W Corsair PSU which, as i have come to expect from corsair, is safe for short bursts up to about 825W.
I am running Catalyst 12.1, but have had the same problem with 11.12 11.11 11.10 all the way back to 11.1.
My proc is a socket 775 LGA "Wolfdale" Pentium clocked to 3.2 GHZ.
I also have 4 1Gb ram sticks made by GSkill. these are also very slightly oced. Not by enough to cause BSOD though.
Thanks for reading this, i hope someone out there knows what the problem is.