Debian Release: 9.7, why is the CPU running at minimum frequency?

Question

linux

Intel(R) Core(TM) i7-7700 CPU @ 3.60GHz
motherboard FUJITSU D3401-H2

The processor always runs at the minimum frequency of 800 MHz, changed cpuinfo_min_freq, the result is 0, what could be the reason?

scaling_governor - performance

cpufrec-info:

analyzing CPU 0:
driver: intel_pstate
CPUs which run at the same hardware frequency: 0
CPUs which need to have their frequency coordinated by software: 0
maximum transition latency: 0.97 ms.
hardware limits: 800 MHz - 4.20 GHz
available cpufreq governors: performance, powersave
current policy: frequency should be within 2.00 GHz and 4.20 GHz.
The governor "performance" may decide which speed to use
within this range.
current CPU frequency is 800 MHz (asserted by call to hardware).

Answer 1

Maybe the system loads it very weakly, or the frequency is limited in the BIOS.

Answer 2

Alternatively, turn off all power savers in the bios.

Answer 3

Now switch to CPU performance in linux
and hop

cat /proc/cpuinfo | grep MHz
cpu MHz         : 4783.797
cpu MHz         : 4906.488
cpu MHz         : 4836.067
cpu MHz         : 4879.911
cpu MHz         : 4832.946
cpu MHz         : 4777.330
cpu MHz         : 4848.571
cpu MHz         : 4785.036
cpu MHz         : 4796.722
cpu MHz         : 4993.816
cpu MHz         : 4843.821
cpu MHz         : 4844.934
cpu MHz         : 4854.708
cpu MHz         : 4949.934
cpu MHz         : 4972.251
cpu MHz         : 4869.818

You can also fix it at the maximum
in this case, I would have exactly 5000 on each
. Depending on the OS, the installation method may differ.