Spike and big drop in miner

[mbacs]

Hi, new to this and pardon if this is too novice a question.

The GPUs on my HiveOS rig periodically drop hashrate to 8 MH/s and then pick up to 16-24 MH/s. Not only that, but temp and fan as well. Is this normal? Here is what I am seeing. 580 and 570 fluctuate the most compared to 1070. Thanks.

[HaloGenius]

Did you use downvolt? Maybe too low
Also check PCI-E Gen version (v2), check risers, power cables