We measured the power usage in three different situations: idle (where we determine an average of 5 minutes), maximum usage during Cinebench 11.5 and lastly the average usage during 3DMark. The idle power usage we measure is lower than what you, as the consumer, will get out of the box, since we perform our benchmark with C-states enabled.
The MSI turns out to be exceptionally power efficient. Together with the MSI Z170 Krait, the Z170A Gaming M5 is the most power efficient board we've ever tested in idle mode, using only 21,6 Watts of power.
Under load the story doesn't change much, again the MSI consumes the least amount of power, though the difference is a quite a bit smaller here. The power usage of the other motherboards is barely higher. This also applies to the ASUS and the ASRock, since their higher power usage is the result of their aggressive turbo mode.
Lastly we have the 3DMark Vantage test for the IGP. Earlier we saw the ASUS and MSI performing the best in the 3DMark Vantage benchmark because of their higher clock speed, but they do this while consuming less power compared to the ASRock board.