I have been adjusting settings for a couple days now.  I am running a 5770 with cgminer -scrypt on win 7x64 with the following
--worksize 256 --gpu-engine 688 --gpu-memclock 1100 --shaders 800 -g 1 --thread-concurrency 8000 --intensity 18

I have adjusted the gpu-engine and memclock to the sweet spot above.  I do see others claiming around 200kh/s but I can't figure it out.  Any help/info would be appreciated. Thanks,