I have the same noise on my Evga 780 Ti. I have tried another 780 Ti from Zotac, again same noise.
My PSU was a Cooler Master Silent Pro M600 600w, thought I would try a different PSU. Tried a new Corsair RM750 and Corsair AX860i PSU, Exactly the same noise.
Stuck with the AX860i PSU as it's a better PSU than my original Cooler Master M600 anyway and I have the power to go SLI if I want to in the future.
I upgraded from a Gainward GTX 680 2gb, that card was in my system since it launched, ran 24/7 and not a single noise, even if the FPS went over 3000 in some menus.
This 780 Ti squeals like a pig at 120fps+ in some games.
If I run something like furmark, the GPU is working flat out and yet there is no coil whine, yet something like folding@home, GPU again working flat out and yet it produces very loud coil whine
Seems to be many 780 Ti cards with coil whine. Apart from the noise, the card runs fast, cool and stable. Very nice improvement over the GTX 680.
Motherboard is an ASRock Z77 Fatal1ty Professional and 3770k.