This sounds exactly like the capcitors next to the CPU. If they are not properly shielded (the copper wire wrapped around them), they emit such sounds. I have seenmore and more of the high end motherboards just putting huge amounts of copper wiring, and some are seeming to use other mehtods now, I think it may be a ferrite core, but I am not sure. I am NO EE, so if an EE is on the board I am sure they can explain it more, and what altrtives to the copper may be.