Help or artifacts are coming!

Good day friends, need Your help

Steadily began to appear on artifacts, usually after 20 minutes in any game (CSGO, the Witcher, Dota etc.), I will say that the settings are not max! In turn, furmark holds 8 minutes on max and nothing, rate is not above 67. Started to appear only today, 4 months no problems.

After the appearance of the artifacts, no action can be done, everything hangs

Comp:
Intel Core i7 4820k
GTX 970 STrix
16gb operatives
mother Asus P9X79