I never tried ectool thermalset … I just assumed that there was an intentional long averaging period on the cpu temp, but that assumption was totally wrong, it was basically ignoring the CPU temp (until 103°C) and waiting for something further away on the motherboard to heat up. You can get instant fan response, if you want it, by setting reasonable cpu fan-off / fan-max temperatures. Here’s what I’m using for now:
ectool thermalset 3 370 380 390 333 363
Translated from Kelvin to Celcius, that’s: fan_off=60 fan_max=90 (and warn=97 high=107 halt=117 but I’m not sure how much warn/high matter). Now my fan comes on in 1 or 2 seconds after starting stress.