HP Spectre x360 annoying noise / coil whine HD

This noise is a real pain in quiet environments and is not related to the fan or audio speakers as HP support "assumes". It is gone when disabling the CPU power states. Replacing the laptop, and replacing the mainboard of the second laptop did not make a difference. It is obviously a hardware design problem and a shame that devalues this nice machine. Similar reports: http://h30434.www3.hp.com/t5/Notebook-Hardware-and-Upgrade-Questions/Spectre-x360-Noise/td-p/5107394