Hi FFrncs2,
Bought a Seasonic x660 and had this same problem 3 times in a row. Returned the first 2 because of this very annoying buzzing/ coil whine and the 3rd I have now is just as loud.
I don't know what to do? Maybe try a different brand/ model. Read that Seasonic parts are in Corsair models aswell.
After researching PSU's for a new system Seasonic seemed to be top of line. Pretty annoyed that they would advertise these x series PSU's as silent when the 3 I've had are anything but.
Been emailing Seasonic USA, they suggested buzzing could be caused by compatibility issues with certain motherboards and graphics cards but PSU buzz sounds the same with nothing connected and started with a paperclip.
When asked if it's worth replacing the x660 yet again or would I just receive another with the same problem (and waste more money on postage), Seasonic support replied "It's worth a try but I can't guarantee it".
How can Seasonic advertise these as silent when the company themselves can't guarantee they will be free of this annoying buzzing/ whining noise?
Do any Seasonic x560 or 400 fanless owners notice this noise? Thinking of trying one of those models.
Sorry for the length, just really frustrated.
Thank you.