PC monitor goes blank during operation. Malfunction of the mains or components?

Question

Iron

During operation, a 3-second black screen appears at random intervals. Artifacts also appear intermittently. Here are the characteristics of the PC:
Overclocking the CPU from 2.6 to 3.1 Hz.
6 devices are simultaneously connected to one (and only) outlet in the room, including a system unit with a monitor, an audio system, a lamp and a phone charger.
I will listen to any advice.

Answer 1

I won’t tell you about artifacts, but I once had something similar. It turned out that the DVI cable was not tightly seated in the socket)

Answer 2

Tons of options, including monitor PSU.