I don't know if theres an industry standard for coil whine deciding if a card is working or damaged, but how much coil whine does it take for you to return a card? Asking since I've only bought 2 cards ever, and I've returned both of them for coil whine, don't know if I'm being too picky or not but I could hear the first (7850) when half way across the room when the sound on whatever I was playing was muted, and on the second (7950) it was about as loud but whined even at idle, although very quietly. Personally I don't see the point in buying an expensive card with a beastly silent cooler if all you'll ever hear is coil whine, but maybe thats just because of my inexperience.
Interesting. How common is it? Bad luck to have two in a row with coil whine, or do you just get good and bad ones? I different build has a 6850 in it (I suppose that makes 3 GPU's then) and stressed that can be heard whining with the case door off and my ear right over it. I was pretty annoyed when I got two considerably more expensive cards making it way louder.