Slows down the computer

People need advice or help, what's the matter?
Not so long ago I started playing hots, i.e. Heroes of the Storm
In it, I noticed that the game sometimes starts to lag "The icon appears from the top" or throw it out, and sometimes even horror. It just starts to stutter and slow down. That is, the frame of the game just stops and everything together with the mouse, and then it starts to play normally. But after 5 minutes it starts again.

When I come home from work and start playing it with friends, then at first 1-2 rinks go well, and then it starts. Or if I minimize the game while loading.

I went into NFS undercover and noticed that the FPS sags a bit, the brakes are barely noticeable and jumps from 60 to 45. Usually this has never happened. I play other online games just fine. But now it's starting to show up on Diablo.
Today I started playing Diablo 3 and noticed the same nonsense begins. What's this?


But some smart people are starting to say that this computer is heating up. Oh, is it?

Here is my vidyuha:





Here is the whole system:




8GB RAM, 4 each "They are old, i.e. bought in the year 2011" maybe because of this?

Cooler:

DEEPCOOL GAMMAXX 200 silent 92mm fan with PWM function



People, please treat adequately, do not write nonsense. Do you need help.