Mhash Fluxuations on Ubuntu 11.04/Windows

[Enisada]

Hello all,

I am new to mining and have a mining rig setup with 4x6950s. Running one of these cards alone nets about 340 Mhash/sec. When I start running all four of them they all will have a fluctuation of 340 down to 200 and bouncing about everywhere in between. I tried both Windows (as it was using all the cores of the 2500K) so moved over to Linux which nets me the same average. None of the cards are overclocked. Any one know how I can get the max Mhash/sec out of this setup? I am getting only an average of roughly 900 Mhash/sec.

Let me know thanks!!

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[1984]

what power supply are you using? My 6950's use up to 200w, I probably can stop typing now.

[Enisada]

I am using an Antec 1200Watt.

[Operations]

Hello Enisada,

which mining software do you use?


Operations

[Caffarius]

The software/options you chose will make a world of difference. It took me a few days to find out the settings my 6950's were looking for, but "-v -w256 -f0" in GUIMiner's OpenCL miner seems to net me the most stable results. After -f, I put the device #. So your first card will be -f0, the second -f1, etc. Putting them all at -f0 seemed to make mine fluctuate like you describe.

[Enisada]

I am using the following.

phoenix -u http://login@gmail.com:password@pit.deepbit.net:8332 -k poclbm DEVICE=0 VECTORS BFI_INT WORKSIZE=128 AGGRESSION=11

[Enisada]

I adjust the DEVICE=X for each card, so 0,1,2,3 for each terminal window.

[Enisada]

Any thoughts on what would be causing this?