I have a Sapphire HD7950, and I just recently got to know that it has a BIOS switch near the crossfire fingers. I have already overclocked the card myself to 1150/1500, but I'd like to know what that switch does.
It's basically a 2nd Bios, so if something happens to the first one, you can use the 2nd one. Basically it's a back up. If you flash 1 and something messes up, you can switch to the other one and use it.