Just wondering, I own a MSI twin frozr HD7950 and have played around with some OCing on it but in the MSI afterburner and Catalyst control center software the furthest it will let me push it is 1100MHz. What are you using to overclock? Or is it just your cards are capable of a higher clock than mine?
I had some issues with Afterburner for one of them, so I used Sapphire Trixx. It could be that my cards just OC a little more because I added almost no Voltage to get to 1150MHz, luck of the draw I guess.
I can actually reach 1200MHz with one of the cards, but then they would be missmatched.