How to increase the speed of rotation of the cooler?

Question

Windows

The nettop began to spontaneously turn off. The CPU is overheating (105°C). The cooler rotation speed is 2000-2500 RPM and this is clearly not enough.
Took it apart and cleaned it didn't help.
I installed SpeedFan, changed the FAN settings in the BIOS (do not monitor, monitor automatically, manually from minimum temperatures). In all modes, the program shows that it is spinning to the fullest.
It turns off even if you boot from a Windows installation flash drive.
Sometimes, with the next reboot, it starts to work like clockwork (≈6000 RPM).
I don't know which way to dig yet. Give advice please.

Answer 1

Sometimes, with the next reboot, it starts to work like clockwork (≈6000 RPM).

I join longclaps - first power the fan separately, and everything will become clear. There it is most likely to be powered by 5V - cut the power wire and apply + 5V from an external source. Do not cut the ground and the 3rd wire - it may give a diagnosis that the cooler is faulty and not turn on. Minus from an external source, connect somewhere with the case.
As a result, next steps.

Answer 2

In fact, the 6000 looks excessively high, not a single cooler that I have ever held in my hands has developed such speeds. By the way, where did the number come from? It's written on it, right? Usually, even the most high-speed (they are the noisiest) have a maximum number of about 4000 ... 4500, and this is obviously enough to bring the temperature back to normal. And if 105 degrees are really gaining, it is necessary, as usual, to check the cooling system: paste, dust in the radiator fins, fit with the entire plane (i.e. is there any grain of sand under the copper plate of the heat sink), the actual thermal conductivity of the heat pipe (it could lose tightness), etc.