I've got a sound like a cricket chirping or a faint bell ringing inside my computer even while it's in standby mode. When I first heard it I wandered if an insect had decided to live inside my case! It started around the time I installed a new Antec TPC-750 PSU. I'm guessing that it's coil whine. Since this is the first time I've experienced it in around 20 years of using a computer have I been lucky or is it something that has become more common with higher quality power efficient components being developed? I've got numerous cheap PSUs and none of them have it and the Corsair TX-750 I used for about 7 years before replacing it with the Antec TPC-750 didn't have it.