Added second GPU and took it out again

I added a second GPU (SAPPHIRE HD 5770 1GB GDDR5 PCIE) as GPU1:

Hashrate is still too low for both cards. Target hashrates are 720 Kh/s for GPU0 (7970) and 200 Kh/s for GPU1 (5770).

Different configurations
After trying out a few cgminer.conf configurations. The system became suddenly very unstable, but with much higher hashrates. I had to do something to resolve this.

Taken GPU1 out again
But I was afraid the PSU was going to be overloaded, so I removed GPU1. Now I'm back to the old hardware setup, hence with this config:

 

The only difference with the previous config is: gpu-threads: 2 (this is the same as the commandline option -g 2). So the 7970 card needs a different value for gpu-threads than the 5770 card. The effect is a really improved hashrate (see next picture).

So this is really nice. Now one GPU has a higher hashrate than two GPUs earlier. But I do want to have the second GPU installed as well. So I will replace the PSU first in the next post.