I'm making a new thread because I've gone through several diagnostic steps and still have not made any progress. The CPU is custom built by me, and several years old.
At startup and shutdown the computer emits a high-pitched whine/squeal. The only times it definitely makes the sound is during boot-up or startup.
Things I've tested so far:
- Removed GPU, still makes sound
- Replaced PSU with new one
- Disconnected HDD's after computer started (so HDD's not on, but computer still squealing; If I don't have them connected the computer won't get past first boot screen and doesn't make a noise.
- Stopped every fan (CPU, GPU, 3 case fans)
It’s at the BIOS screen that it made the noise.
It seems like it's coming from the CPU unit, but it is a high-pitched sound so it's hard to localize it. I'm thinking about remounting the CPU, but I need to go get some thermal paste. Could that be the problem? Any other diagnostic steps I should take? I'm baffled.