It's a KFA2 (Galax) GTX 970. I got this card a month ago and returned it because I thought it was coil whine. Got the replacement today, exact same sound.
It only buzzes when I'm playing a demanding game. If I'm playing a less demanding game it doesn't buzz. I just started up GTA V when I recorded this.
Unfortunately, from what I understand, this is a common issue with these cards. As reportedly they have various noise issues from their "super high quality" components. I don't own one, nor have I seen one in person. I don't know if there is a fix for something like this, but I would assume it is either the fans or conductors, also don't take my total word for it because I still do not know a lot about GPUs and such.
I watched a review on this card a while back and I recall it mentioning something like this. I would say your card is fine from what I remember it was very loud.
There is nothing you can do really. All 970s have coil whine issues, as in all manufacturers have the same problem. I got a G1 gaming card and it had bad whine, didn't even bother RMAing it, didn't want to get another whining card. Got a 290x and couldn't be happier.