It can be your GPU
Or Your monitor
And even the RAM can cause these type of problems
Even overclocking, voltage to the ram and a broken cable can cause these type of problems.
And if it only after mining then the others already answered the question.
If not then.
Connect your monitor to your Mobo
And if it does the same then it can be your ram or monitor
Ask one of your friend if you can try their monitors and if it does the same thing then it's the ram.
Btw nice wallpaper