I'm not sure what it could be. I recently switched out my GPU thinking it was coil whine, but the sound is still there. My guess now is that it is one of my fans, how do I check to see which one is producing the sound?
Unplug each case fan one by one. Put your finger on the fan center to stop it for a second unless you hear the squeaking stop. Well that I can't formally recommend because someone may cut their finger off sticking it in the fan rather than the center piece, but you get the idea. Process of elimination.
Unplug each case fan one by one. Put your finger on the fan center to stop it for a second unless you hear the squeaking stop. Well that I can't formally recommend because someone may cut their finger off sticking it in the fan rather than the center piece, but you get the idea. Process of elimination.
What computer tasks make the sound the loudest / most prominent? Is it always there?
If it turns out that your fans are not the issue, you could try running your system with no GPU on integrated graphics just to completely rule out the GPU. Coil whine on GPUs is a common thing, so it is possible that the new one also has coil whine.
As nuke master said I would uplug one by one fan then if you still have the issue look at your power suppy I have had old ones in the past make a pitch noise that annoying.