When I compare them it seems the 6950 has better memory clock and more processing cores..?
Cheers. Also, the case is very old, but I'm not looking to spend a lot on a new one and would only want to do so if really necessary. Would this have a large impact?
Why not go to haswell? I know there isnt much perfomance difference but why not get the latest and greatest?
Otherwise, its not always about memory clocks and processing cores, I agree with obsma1, pick the 7850 or push that slightly to the 7870