I just picked up 2 of these cards on Craigslist for $150 total.  Out of the box, I am getting 600kH/s.  I want to push these things for another 50-100 kH/s each.  I have been looking online and it seems some people have had success with this, but I can't find a good method on how they did it.  Can anyone recommend improvements for my current config?  I am running modded cgminer 3.7.2.

-I 19 -g 1 -w 256 --thread-concurrency 8192

Thanks!