anyone who has experience running ubuntu?
Recently had to use an older computer for my cards, running ubuntu 12.10 32bit with 2gb ram and cgminer 3.5.0, using the latest drivers from amd. I have a 6950 and a 6970 but only getting around 500 kh/s with both cards combined, compared to 900-1000 I had when running on a win 7 64bit 8gb ram computer (also 3.5.0).
I don't have any special settings, just the pool information and an intensity of 19, no hardware errors, GPU_MAX_ALLOC_PERCENT 100
and GPU_USE_SYNC_OBJECTS 1 has been set.
I have heard that Linux is more difficult to use the overclocking tools than Windows. Also, if you have any questions on what others are getting, I would check
https://litecoin.info/Mining_hardware_comparison. I suspect it's the driver version you're using in combination with the SDK version. If you're running a ATI HD 7xxx series GPU, you'll want SDK 2.8 but if you're not, I hear 2.6 is the way to go.
I don't personally own or run anything other than ATI HD 7xxx series GPUs, just giving some suggestions. Good luck!