Check out this link (assuming you're mining LTC):
https://github.com/litecoin-project/litecoin/wiki/Mining-hardware-comparison642kh/s
--shaders 2048 --thread-concurrency 8192 -I 13 -g 2 -w 256 Card is a Gigabyte GV-R797OC-3GD, Catalyst 12.10. Wattage measured approx. with killawatt-ez. Operating temp is 72C. OC done with MSi Afterburner. GUI interaction/100% cpu lowers hashrate slightly.
580 kh/s:
@ 256 Worksize @ vectors 1 @ Aggression 13 @ threads_per_gpu 1 @ sharethreads 28 @ lookup_gap 2 @ gpu_thread_concurrency 24576, 13.1 drivers. -- Gigabyte GV-R797OC-3GD (GPU & RAM overclocked)
In the first one, thread-concurrency is way lower than yours, and it's a bit higher in the second. Share threads is way lower in the second. I haven't actually messed with any of this yet... just posting so you can look at it as a comparison.
I'm not sure what the difference is between the Gigabyte and the Sapphire or if you would be able to safely use the same settings, you would probably have to research it to compare. Are you overclocking? Also what drivers are you using? Looks like 12.1 and 13.1 are being used above. For whatever reason, I've heard that some drivers work better than others depending on the chipset.