Quote from: jt72 on June 30, 2013, 10:56:44 PM

Hi all,

I have tried a few times to setup cgminer and Ubuntu 12.04 with 2x 5850 or 2x 5870 following the guide here:
https://docs.google.com/document/d/1Gw7YPYgMgNNU42skibULbJJUx_suP_CpjSEdSi8_z9U/edit

I used the steps for AMD Raedon 7xxx Series drivers, because it seemed simpler and I wanted to just get things started...

Each time I do it, I end up having correct performance if using only one of the GPUs, and it doesn't matter which one. Any time I try to use 2 GPUs I would get diminished performance. For example if I was setting up 2x 5850s and getting 350MH/sec for one each I'd probably get only about 400MH/sec when using both.

This was not the case when setting up Windows 7, 64-bit, cgminer versions 2.11 through 3.1, and using a few different versions of AMD drivers/opencl. The last setup I did was with AMD ver 13.1, which includes opencl.

I'm wondering if anyone else has either had success with linux (ubuntu preferred, but don't really care) and running multiple GPUs at full potential.

Cheers

What arguments are you giving cgminer?