After almost 8 years of wondering why Mac computers (e.g. 2013 and 2020 Macbook Pro for my part) were overheating so much (reaching 100°C on both models when fully stressed) with Windows (installed with or without bootcamp), I finally discovered why thanks to your hint @Techno:
My guess is that Mac motherboards do not handle the turbo boost mode of modern CPUs. It is probably handled directly within MacOS, therefore Windows is lost and keeps using 100% of the maximum possible CPU frequencies. But the CPU turbo boost mode should be used only for very short periods of time, not all the time like it does here.
On Windows OS, go to the Advanced Power Options, and then under "Processor Power Managment":
- first set "System Cooling Policy" on ACTIVE for both Battery and Plugged in (by default set on PASSIVE on Battery, but it seems wrong except if you lower the "Maximum Processor State" a lot (maybe like 50%).
- then set the "Maximum Processor State" at 99% for both Plugged in and Battery (lower on Battery if you want to save it). That's it!
If you open HWMonitor while doing this, you will notice that your CPU frequencies drop directly to the normal frequencies of your CPU (e.g almost always at 3000 MHz before = turbo boost frequencies, and at 1995 MHz after the fix). If you go lower than 99% you will notice that the frequencies change with normal ratios.
The downside of this is that we loose the turbo boost option of our CPUs, but in my opinion it is better than having the fans always running at their maximum, and damaging your hardware (CPU, but also the motherboard itself when it reachs 100°C!)