GPU temperature -> the lower the better (less leakage currents -> reduced power consumption)
fan speed -> the lower the better (cheap sleeve bearings...)
So I've recently put my rigs on the balcony, got me into the range of 40-60% fan speed and 30-50 °C GPU temp (before: 70-100% and 60-80 °C), reducing the total power (at the wall) by more than 10%.
People placing their rigs on balconies/outside have no issues with humidity (not to mention rain, etc.)? I was wondering if I could do that but it is too cold outside now (-18C at noon, up to -25C at night)
My open frame rig running on balcony have a transparent foil cover the front/side/top of the frame, I think the actual temp inside is still above 0 degree even the outside temp is -20C, I still need to set the fan speed above 30% to keep the GPU temp less than 60C, which is my normal target temp area. As long as the machine is warmer than environment, there is no risk for condense
But when the machine hangs for a couple of hours (due to too high overclock, unstable gpu etc...), the extreme low temp will hurt the fan bearing, those fans have become so noisy recently that I plan to take them apart to re-oil