I've added a 2nd 6950 recently. Both cards are unlocked and stable up to 965MHz @ 1145mV. My new issue is that my gpu core speed fluctuates terribly when I overclock (via MSI afterburner) it past 820mhz. When I set the clock clock to 965mhz, the core fluctuates between 965 and 790mhz, which is making me lose about 30mhash/s on each card.
I kinda had this problem when I had just 1 6950. My "solution" was to go into catalyst control center and set the power control to anywhere between +10 - 20%, which would stabilize my gpu clock.
If I try to do this now, my core clock drops to the upper limit in CCC, 840mhz.
Does any know any tricks to keeping the power control setting in ccc without the core clock being lowered?