HD5750 X2 (crossfire)
Windows 7 pro legit updated
Latest non beta catalyst drivers
Latest non beta AMD SDK driver
cgminer 3.7.2 (3.8 does not support GC anymore) with cgwatcher (latest).

-I 18 -g 1 -w 256 --thread-concurrency 6016

I have improved the conf, i'm on 400 Kh/s now.