Why does the memory not work at the declared frequencies?

Question

RAM

Good evening.
Purchased 8 GB memory 2 pcs. Patriot Memory VIPER 3 PV316G186C0K .
Its speed declared by the manufacturer is 1866 MHz
In the dispatcher it shows that it works with a frequency of 1600 MHz
The motherboard and processor support 1866 MHz
Why does it show a frequency of 1600 MHz then?
I am attaching the necessary screenshots.

Answer 1

Increase the frequency in the BIOS and you will be happy.