I am now getting about 730 kh/s on mine, using TC 8193, gpu clock 1065, memory clock 1500. Staying at 72-73C at the moment.
Also lowered my screen res to 1024x768, and made sure what is displaying on the screen is static. As soon as something is moving (cgminer window, or whatever) the hashes go down to about 690. Yes, I know, crazy.
With those exact settings I get 717 Kh/s, so it's a bit better than before. First setting where a clock above 1050 isn't counterproductive.