I'm finding that with my shader unlock 6950 I need more voltage for the same clock speeds to be stable in BF3. Usually I run 930MHz @ 1.200V for mining, and it's stable at that all day using -v -w 128 flags, but for BF3 it keeps crashing even at stock memory clocks so I have to either increase the voltage or decrease the core clock speed. I thought that mining would place a lot more stress on the card than gaming, and therefore present stability issues more quickly than gaming. The card is otherwise fine.
BF3 dosen't like overclocking on most systems,be it vid card,CPU,RAM or Front Side Bus
The 6950 (unlocked shaders by soldering a wire) I have on my second gameing puter only likes to play BF3 @ 900 core clock & 800 or higher mem clock,no overvolt.
My 6970 crossfire setup is the exception-925 core clock & stock mem clock,20% Power Control Setting works well in game & gives me 422 mh/s per card
I had my 965 CPU up to 4.2 & my RAM OC'ed to 1880mhz,but BF3 would stutter pretty bad until I reverted back to stock settings