What to do with the processor frequency (drops under heavy loads)?

Question

laptops

I ask for help, maybe someone knows what it is when surfing the Internet and using basic programs, the processor frequency is stable up to 4 GHz
as soon as I turn on a game or, for example, a test in AIDA64, it immediately drops to 0.80 GHz after turning off the load, everything returns to a frequency of 4GHz

Acer nitro 5 laptop
Intel core i5-8400H 2.40GHz
Nvidia geforce gtx 1060 6GB
8gb ddr4 2667MT/s

The problem occurred after reinstalling Windows
I also noticed that the cooler began to work quieter and any manipulations to increase its speed were unsuccessful. impossible because there is no way to configure anything.
I installed all possible drivers and the like reviewed all the videos on Youtube, nothing helped.
Now Windows 10 ltsc is completely clean, it broke its whole head, maybe you are aware of the solution and someone can help.

Answer 1

This is overheating and throttling.
First, install all drivers from the offsite.
If it doesn't help, try to return the OS as it was (if the recovery partition remains).
If it doesn't help, check the cooling. Perhaps the cooler is broken or it's time to change the thermal paste, and reinstalling Windows is a coincidence.