Just bought a new pc, the whining noise in the PSU only happens when the 24pin cable is plugged into the motherboard, and stays constant, no changes in pitch except when I turn off the power to the psu, after about ten seconds the whine rises in pitch then stops.
Ive replaced the psu twice (corsair cx500) and the same problem still happens so is it just a dodgy motherboard? does anyone know of any fixes to this? its an asus P8H61-MLE
What you have is called "Coil Whine" and usually comes from the power supply but could be from another component. Lots of people have the problem even after multiple RMA's and sometimes you just have to go to a different brand.