I have the Sapphire 7950HD (11196-16-20G)

It can do 690-700kh/s at 1175/1600 1.15-1.2v with the right settings in cgminer.

Xfx is great for the warranty but suck for hash speeds. I have 3x Xfx 7950s that only do 630kh/s and clocks only reach 1075/1375 locked voltage at 1.25v
I will never sell the XFX cards, they will go in my gaming computer eventually. The lifetime warranty is unbeatable.