setx GPU_USE_SYNC_OBJECTS 1
cgminer --scrypt --intensity 17 --worksize 256 --lookup-gap 2 --thread-concurrency 22528
630kh/s on Gigabyte GV-R795WF3-3GD rev.1 (Catalyst 13.4)
Could try more aggressive settings, but VRM temp is too high (95 C).
My record is 700kh/s on this card with Catalyst 12.8 + AMD APP SDK 2.6 with "--intensity 20", but VRM temp was going to 120 C.