Semiconductors love 40C - people hate 40C.
Even if your ambient is 50C - with shitloads of wind, your ASICs will be fine. Heat is not the problem miners face. Heat accumulation is. Vent out the ceiling and blow, blow, blow. An AC is a horrible way to move heat outside.
Yes semiconductors love 40C. But you don't get anywhere near 40C with air cooling. The tempurature difference between the ambient air and the asics is the real killer. I would guess the dT is more than ~40C.
40C ambient with lots of wind = 60C at silicon
40C ambient with little flow = 90C+ at silicon
40C ambient with very serious airflow = even less than <60C
air flow is VERY cheap
air conditioning is very expensive.
400cfm is really not much for 2.6kw.
20C dT is good even for high end heatpipe heatsinks with ~100cfm fans per 150w chip.
Anyone know the actual temperature difference between the chips and intake air for the sp10?