Question Is the problem my PSU or motherboard?

Nov 25, 2021
From time to time, this happens to my computer:
  1. I turn on the computer for the first time on a given day.
  2. It boots up normally.
  3. Suddenly, 5 minutes or so after booting up, there’s no image from the GPU or the integrated graphics card anymore. The GPU LED indicator goes off too, but all fans still spin normally.
  4. I try to boot it up again multiple times, but there’s still no image or GPU lights, but both the CPU and GPU fans spin normally.
  5. I wait for some hours and try to boot it up again. The CPU fans try to spin at an unusual high speed and the GPU lights are back, but still no image.
  6. Right after #5, especially after the unusual high CPU fan speed, everything goes back to normal and it works fine throughout the day and the following ones.
  7. After a few days, it all happens again. The interval is usually a week, but it might be decreasing.
  • My computer used to restart randomly a while ago after using it for some time, but I was able to use it again normally after the restart. This problem has never happened again since I turned off “fast startup”. It’s been months now, maybe a year.
  • Right after an intensive use like playing video games, my PSU starts to make a subtle clunking noise for a few minutes and, then, goes back to normal again.
  • BIOS is updated.
  • Formatting my computer didn’t make any difference.
  • CPU: i3-8100
  • Motherboard: Gigabyte H310M m.2 2.0 (rev. 1)
  • PSU: Gamemax GM500
  • GPU: PNY GeForce GTX 1060 OC (3 GB)
  • 16 GB RAM (x2 8 GB in dual channel)
  • HDD: 1 TB Toshiba PC P300
I didn’t overclock anything.
Nov 25, 2021
So, I bought a new PSU (a Corsair CX550), but the problem still remains.

The problem is intermittent; it works fine for a week and then it happens again. If it were the mobo, wouldn't it fail every single time or, at least, way more often?

I'm temped to buy a new motherboard and CPU (it's also time for an upgrade), but, at the same time, I'm afraid of spending money on something that expensive without being sure what the problem really is.