I've seem to run into a little issue here, nothing major but I want to have some peace of mind.
Today at around midnight I decided to play some "Little Inferno" and the PC started making this squeeling sound very very thin but audible, I thought it was the CPU fan at first but ended giving up without knowing what it was a couple of minutes later I decided to change game, to Saints Row 4, the sound as there once again but much quieter, almost not there at all, when I alt tabbed off the game the sound stopped and alt tabbing back in would make the sound resume, the temperatures seem to be fine and i've tried setting the GPU fans to 100% , wasn't able to reproduce the sound, could this come from faulty drivers of some sort or is something seriously wrong with my system?
Intel i5 3570k @3.4GHz (Not overcloked with stock fan)
Asus GTX660 Direct II CU TOP (GTX660-DC2T-2GD5) 2GB
Corsair Vengeance 8GB Ram 1600MHz
Windows 7 Ultimate 64Bits
This is known as "coil whine" and is quite common among GPUs actually, it depends on how hard the card is working, and can be affected by over/under clocking as well as your PSU. It is not harmful to your card in any way.