I also highly recommend Kalroth's version of cgminer! The xIntensity feature allowed me use 2 threads with my 7950, getting it to hash on par with my 7970!
http://k-dev.net/cgminer/You're getting over 700KH/s from a 7950?

I'd like to see the config for that, I played around with two threads on my 7950s and they hard hang almost immediately.