Of corse, i confirm this !
for exemple , my T9+ at 10.5TH
chips at 105c = 1170w arround
chips at 80c = 950w arround
And bitmain confirm this !!! just look exemple for T17
Power efficiency on wall @25°C, J/TH 55.00 58.85
Power efficiency on wall @40°C, J/TH 58.26 62.34
so , just try this !!! run S9 with fan full speed , look temp after 3min (stabilise temp) and run with same config but config the fan at low speed (to force up temp) ... and look power is more !!!
Or for test, run S9 with fixed fan arround 20% ... at startup ... just look the power up every segonde !
So ! but this theorie is only true with fixed fan ... at autofan, the chips temp is regulated, the ambiant temp is 10 or 40c , just the fan speed change but the chips temp is arround same value! so, the power consum is only difered by fan power...
Is valable at all miner, if you run this on lowtemp environement, run this with fixed fan (upper than original) for force down temp chips, and seed the efficiency, is better