When my box is off it makes a buzzing noise from the new Corsair PSU. It's just a slight little noise that you have to get close to hear, it sounds like a little transformer. Power switch position doesn't matter, as soon as I plug the power in, it buzzes. It's plugged into a surge protector/power strip. Never had this happen before with a PSU. I'll gladly exchange it if I have to, of course. Just wondering.