We measure the power consumption during two scenarios: idle (where we determine an average based on 5 minutes of idling) and under load, where we measure the maximum power consumption during Cinebench 15.
As per usual the motherboards with the least amount of added features consume the least amount of power - of course the absent extra chips and controllers do not consume any power. Because the MSI Z370 Godlike Gaming was tested in combination with a GTX 1050 Ti (this board does not have its own video-outputs and can therefore not utilize the iGPU), it consumes more power, which especially stands out in idle.
Under full load the ratios between the motherboards are not that different. The Gigabyte Z370 HD3 and HD3P are still the most efficient, while the other motherboards are not far above them.