I see many here using phoenix, and a bunch of the other ones but the one that has worked best for my 6950 is GUIminer w/ these settings:
New Miner -> OpenCL -> parameters: -v -w128 f1
My card cant be unlocked and I have the core OC'd to 890, default voltage. RAM is at 150mhz.
It produces around 363mh/sec
Ive tried phoenix, w/ the different kernels but it gets nowhere near that many mh/s on my card.
Im running the 11.7 preview drivers for now.
Please post any other miners I should try and the parameters.
im running the same miner and settings when im not using my pc, when using it i use phoenix with a aggression=6 for around 320 Mhs while watching videos. I have my sapphire OC'd to 900 and ram at default and get 365mhs (with the miner you have listed above, plus my backup pool settings.) and using 11.6 drivers