A few months ago, my FSP AX500 PSU started making a noise sounding like a coil whine. I thought nothing of it and left it alone. But then, yesterday the noise got louder. This a really good 15 year old PSU, but should that be a concern?
Btw, it has been siting in my dad's old build for years, and when I got a shitty prebuilt, I started using it, then I built a new pc with the PSU.