Consuption drop in some time

Hello, everyone!

After launching ETH mining process, I got normal consuption rate (about 1000W). But in about 10 minute is decreases to 200W. Though, still writes in console, that I’m receiving about 200,000 kH/s of Hashrate. How is it possible with such high drop of voltage?

Got 8 cards (GTX 1060 6Gb x4, GTX 1070 Ti 8Gb x4). OS version: 0.5-82.

Please, if someone has already faced and solved this problem - share your solution! Or just give an advice what to do in this situation!

P.S. After 10 minutes got this (20-30W instead of 100-150W):
after10

Got this at the beginning of minning: