i have one of my sp20 feeded by 3 psu with 18awg: corsair 550w for 2loops, 2 nonames for the other 2 loops. settings as posted yesterday:

Temp Front / Back T,B    12 °C / 55,54 °C
Fan Speed    70
Start Voltage    0.67 / 0.67 / 0.67 / 0.67
Max Voltage    0.72
Max Watts    220 / 220 / 220 / 220
Mining Rate: 1439.78Ghs

is true that ambient is pretty low, like 5-10C. cable might be warm a bit, can't really say for sure

got an dps2000bb with special board and 16awg cables. full load ~300w and cables still at room temp!