I've got a full rig of 1070 g1 gaming cards and they wont overclock on core past +50 on 100 % TDP without the miner going crazy with ridicilous high hash numbers.
On 100% tdp these cards are pulling 185Watt. The 4pin power adapter only deliver 150W. so 35W is pulled from the mainboard. With 6 cards in the rig you need at least 1300PSU gold rated and powered risers.