Most people can't hear the whine. You are one of the unfortunate people. I have the same problem. I could hear the whine from the LCD screen on the LG-VX10000 Voyager. I can hear the whine on my Asus GTX-670 DirectCUII. I can hear the whine on the seasonic psu I bought for my wifes computer and when CRTs where around back in school I was the only one in the class that could hear the damn things.
I personally do not think it is a sign of impending doom I also doubt that seasonic will RMA a PSU for coil whine.
I would try to RMA if the shipping is reasonable or see if the store you purchased it from will swap it out for you. I usually get my way from Tiger Direct, Fry's, Best Buy and Micro Center. Any online retailer probably wont do that for you though. I have even made Best Buy ship in warranty things to the manufacturer on my behalf. So see if there is a way to get it exchanged without you forking out money for shipping. Otherwise it is up to you whether it is worth the money to RMA it coil whine.
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