High Pitched Whine upon Booting

[introaether]

When I turn my PC on, there is an audible high pitched whine. This lasts until windows 7 displays on the screen.

Haven't had any issues with performance.

Any ideas what this might be? What is the system doing when booting that might cause the noise that it isnt doing when actually up and running?

Thanks all.

 

[CountMike]

So called "coil whine" (if that what it is) usually comes from PSU and VRM either on MB or GPU and can occur at varying loads so you'd have to open case and listen to it carefully at those places.