cgminer versions 2.11.3 and up can be used to mine with high thread concurrencies now. Follow these instructions:
WINDOWS: Open console and type
Code:
setx GPU_MAX_ALLOC_PERCENT 100
Now, close the console (it will not work if you open cgminer in the same window). Open cgminer using a .bat or a new console, high thread concurrencies will now work.
LINUX: Open terminal and type
Code:
export GPU_MAX_ALLOC_PERCENT=100
Now high thread concurrencies should work in cgminer.
From:
https://bitcointalk.org/index.php?topic=117221.msg1256502#msg1256502cgminer --scrypt -w 256 -v 1 -I 20 -g 1 -l 1 -T --thread-concurrency 21712
voltage - 1087
core - 1050
memory - 1500
I do not have Sapphire, but this gives me 630 kh/s on my 7950s. (MSI)