I have noticed, that adding more GPUs to my rig, lowers the sols per GPU.
3 x 470s = 15 sols per instance.
5 x 470s = 13 sols per instance.
That sounds plausible, because more and more GPU's saturate the CPU cores, so CPU throughput becomes the bottleneck. Especially with nvidia cards, CPU load of this miner is quite high.
I wondered that. cpu at ~60%.