In all cases.
* Replace the stock thermal paste with something reputable, use Arctic MX6 or MX7 or an equivallent.
* On BitAxe, ditch the dodgey low cost heat-sink. take the time either to buy a BitAxe with a good heatsink or buy one like the Thermaltake AXP60-50 "Copperzila"


* On the
NerdOctAxe prior to and including V3.1 the thermal management monitoring is a complete joke.
The temperature sensor is placed over 10mm away from the actual ASIC's so its idea of temperature is way off I expect there's frigs in the software to compensate for the lets face it a
CRAP design.
The only recommendation here is to crank the fan speed to maximum and hope the thermal paste doesn't give out, because the reported temperature is not the ASIC temperature.