I had coil whine on my GTX980Ti.. fixed it by getting a good UPS that cleans up the power output to a clean 60Hz sinewave.
The inducer coils on your graphics card are there to clean up input power going to the GPU. So if your house, apartment, ect.. has really noisy power you'll get more noise of the coils. My card was pretty noisy until I put my PC on a UPS.
Also your power supply can make a huge difference as it's converting AC Power to DC Power... if your power supply is of poor quality it can introduce a lot of ripple into the DC current. Also this depends on the AC input from the wall, so again a UPS is highly recommended!!
This Corsair RM750 review shows ripple test:
Even the best power supplies will have some ripple, but you definitely want to minimize it.