I don't really think the above is what the problem is here. I find that the 970s are buzzing and making other noises, at much lower FPS. I cannot play Battlefield without hearing one of my two MSI 970s whine away.
The other one is not as bad, but if u wanna hear it, you can, especially if the case is opened, but the 2nd one, boy, in a noise damped R4, gaming with a headset, the 2nd is still audible.
I've had a 280x which was far worse, and a 670 which got returned because of it aswell, none of the 4 780s i owned, all reference by the way, had any coil whine whatsoever.