Think it's Nvidia SMI issue, in fact, if you connect hardware wattmeter you won't see any power fluctuations or overconsumption. All this is configured on the driver and controller side, so this may be only specific hardware-related thing (factory OC'ed cards and so on). Also it can be caused by kernel specific. I'll look into 1070 kernel and update binary if find a way to make it smoother. Just check for updates on the thread from time to time.