I got two rigs now running both identically the same apart from one rig gpus are flashed and the other are just boosted with MSI afterburner. I noticed that PSU of 1000 watts is to small and them cards require at least another 200 watts on the top.

The rig with cards that are not flashed lacking only about 25 mh/s. I have not yet checked the actual power usage with a device on this rig but the first rig with flashed gpus continuously draws about 1100 watts.