Just bought a Gigabyte WF x 3 HD 7970 card. I lucked out and got a rev 1 which means it is not voltage locked! Yay!! Also, out of the box it has proven to be a great overclocker. Easily hit 1150/1550 with no voltage increase, all while staying unser 55 C.
The only issue I have is that it does have some coil whine. Now, this was purchased for a new build, and all of the parts have not come yet. Currently I have it in my 4 year old PC with a 4 year old power supply, and I suspect that it is possible that the power supply is causing a part of the problem.
The coil whine doesn't really bother me. I can make it out in my HAF 932 case. The new build is going in a FT02 and I play with headphones on, so I doubt I will really even hear it.
I am just wondering if coil whine is damaging to the card? If so I may need to RMA it, but I do not want to as I feel I've won the silicone lottery as far as it being a rev 1 Gigabyte card and being a great overclocker.
Coil whine in its self isn't a big problem depending on the type of coil in question. SMD mounted ferrite shielded inductors (coils) are the ones to watch out for as they often degrade and fail over time. The other types are all ferrite core and they can buzz from time to time depending on the vrm circuit that drives them. The problem is when they overheat and the insulation begins to degrade allowing current to pass into the core or the shell allowing the windings to short. Not only does it weaken performance and stability some can completely fail thus not allowing no or very little current to pass it all. It is like switching off vrm phases so the rest has to work hard to drive the same current load as before. It can cause the rest to fail much sooner than the first coil as the load is carried with fewer phases.
In the end it all comes down to which type and the build quality of that coil. Other factors are mainly the circuit, temp, and if there is enough capacitance (high enough rated cap) to really get the most. When there isn't enough coils tend to buzz more often than either wise.