Quote from: g0re79 on December 19, 2013, 08:43:40 PM

Quote from: sprmacholo on December 19, 2013, 07:30:49 PM

Quote from: Hazado on December 19, 2013, 07:12:40 PM

Quote from: sprmacholo on December 19, 2013, 03:58:25 PM

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.

export DISPLAY=:0
export GPU_USE_SYNC_OBJECTS=1
export GPU_MAX_ALLOC_PERCENT=100

Make sure your running those commands before every cgminer starts
May want to look into setting your thread concurrency on each card to see if that helps
Some settings here - https://litecoin.info/Mining_hardware_comparison#AMD_.28ATI.29

Help with undervolting - http://www.cryptobadger.com/2013/10/undervolting-in-linux-via-modified-bios/
Good thread to help get you running - www.reddit.com/r/litecoinmining/comments/1fb5qs/step_by_step_headless_linux_setup_from_scratch/

Thanks for the help, though I have tried most of that. The undervolting guide is unfortunately only for 7xxx cards, but I solved that by using AMDOverdrive, while at the same time overclocking the card. Thing is they have a lower hashrate overclocked on the ubuntu than they had on the windows machine on stock settings, I tried settings various thread concurrencies and work sizes but it doesn't make a difference. As of now the 6970 is on around 360 kh/s, and the 6950 around 300 kh/s, compared to 505 and 420 while on the windows machine.

Edit: I tried severely undervolt and underclock the 6970 and the hash went up with about 50, thinking there is something fishy with my settings

Firstly let voltages on their defaults (You can lover voltages later when everything will run smoothly) and find best HR peak by setting default clocks on both CORE/RAM and then increasing (or even decreasing) them by 10 MHz on the fly, while CGminer run. Some cards do their best underclocked a bit and some do even better with the same engine / memory clocks.

did pretty much this, worked much better. Strange that I didn't experience these issues when I overclocked in windows.

Oh well, all is well, thanks people.