Managed to get one of the Zotac 5080 Solid OCs which arrived today, it certainly has some coil whine but not intollerable to me.
My case is a Fractal North XL mesh with the three stock Fractal fans in the front, Arctic III 360 up top and one additional 140mm Arctic P14 at the back so not a silent build by any means but it is virtually silent when idle and even under load the fans and pump don't seem to really work too hard.
Appears to be worse when the FPS is very high - running Timespy at 1440p when it hits 250+ FPS it is auidble from about 50cm away with my case up on my desk, outside of those scenarioes though it seems to be fine to me though.
For my uses it is fine, and certainly with a pair of closed back headphones for gaming use I cannot hear it at all.