My GTX 970 had a bit loud Coil Whine from day one till today (3 and half years after). Frankly if i didn't use haedphones, i would had it already replaced. In my old pc even motherboard Coil Whines depending the music playing in the bagkround whenever is Realtek on board or NVidia's card HDMI audio.

Oh, i am sorry. Has* is the correct, my bad. Nothing stops it. Neither another motherboard nor other PSU (I have changed 3 PSU's for other reasons all these years). Not even the pinch of noise changed a bit.

The same was said for 900 series. I have a supposedly higher quality board design (FTW) and a friend with a cheap blower type model doesn't. Even my ASIC quality is so bad that i can't OC even a bit cause i have crashes in some games like Witcher 3. It's totally random and the only other way except applying a frame cap to me is to heavily power limit the card with unlinked power to temp ratio.

I noticed that sometimes increasing the voltage by a few bits in EVGA XOC helps.
Other times it's actually the fans (where 2 or more fans, are in sync with one another, generating a higher pitch sound or whine). It often is more audible above 75% of fan speed; and oftentimes lowering one or two of the fan speed, solves that.
Or, it could be one of the fans is actually touching something, like a cable or something, that's causing the sound..
 
Sometimes it's the capacitors. They swell and shrink with electric voltage. It's only a tiny bit.
But larger size capacitors being 'filled' and 'emptied' several thousands of times per second, can make them 'sing'.
They literally buzz, creak, or have a high pitched tone, depending on their charge and discharge frequency.