Seasonic M12D 850W power supply makes a high pitch noise while on
So I bought the Seasonic M12D 850W PSU, which is supposedly their top of the line power supply. I read a few reviews on Newegg which indicated that a few people had some problems with the power supply. The thing is, I’ve spoken to enough people to realize that Newegg isn’t the best place to base a purchase off of reviews anyway.
So, I bought it.
I recieive it, plug it in, I immediately hear a loud, high pitched noise coming from the power supply. Had I not read about this I would have never known and probably guessed that it was some other part that was faulty. Sure enough, it crossed my mind and it immediately clicked. I have a power supply that is making a really loud coil whine.
I searched Google for “Seasonic M12D 850 high pitch” and found several sites which indicated that this is basically coil whine. What is coil whine? Well there are coils in the power supply which get wrapped and unfortunately due to QC issues, not all are wrapped the same thus causing some coil whine or vibration to occur. This in turn causes the high pitched noise to come out of the power supply.
I bought it from Amazon so I ended up requesting an RMA. The second power supply was sent to me. I received it at work, plugged it in to a test computer and sure enough, the high pitched noise was still there. I was extremely disappointed to receive a second PSU with the same exact problem.
I finally called Seasonic USA and spoke to a lady at first who attempted to help me. She finally ended up transferring me to a male who told me that the noise I was hearing is not normal. He ended up laughing at me because I was so adamant about the noise. I said, so you’re telling me that the power supply should not be making any noise? He literally laughed at me and said yes, the power supply should not be making any type of weird noises.
That was enough of a recommendation and reassurance that I felt that I should RMA it directly to Seasonic. So I did.
They just cross shipped one out to me so I have to return this one in a day or two. The thing is, I still have the one in the computer which I will have to return to Amazon once I received the one from Seasonic.
All I can hope and ask for is that the one from Seasonic does not have a high pitched noise. According to many forums out there, the coil whine actually does not harm the power supply nor is it on its way out. It’s just poor QC and it will be ok as long as you can get used to listening to a high pitched noise.
If anything, my honest recommendation is to replace it with an RMA and hope that the one you get is working properly.
Update
So Seasonic sent me an RMA’ed unit. I asked for a unit specifically without any type of high pitched noise. What did I receive? A GOOD POWER SUPPLY! Noise free of course!
Goes to show, when you want something, go to the source. I tried Amazon and yet received another flakey dud. It appears that the model that Seasonic sent me is fairly new. I compared the serial numbers and if I assume that they base the serial numbers in sequential order then it would indicate that the PSU that I was sent is much newer than the ones I bought and received from Amazon.
On top of that, the unit has different cabling. It’s weird. Very weird. I am just thankful that they sent me a unit that does not have any high pitched noise.

I have the same 850w psu, and am getting the high pitched whine. You think I should contact seasonic directly? I don’t want to pay return shipping to newegg after I just had to dot hat for the motherboard. Thanks.
Russ,
Yes I would contact Seasonic directly.
Hi,
Can you by any chance, list down the 2 serial numbers which have high pitch noise and the newest serial number with no noise.
I am planning to buy one but want to avoid the older batches.
Thanks.
the serial number of my defective unit was R0907AA271370076.
Unfortunately I wasn’t lucky enough to be cross shipped a replacement.. they said I had to wait. Also, their RMA person is out on vacation the whole week, so it’s been quite hard to even find someone to talk to. What a let down. I’m considering going with a corsair just because of their unprofessionalism, and unwillingness to admit to their quality mistakes.
This was the defective part #: R0907AA171040034.
I have to find the box for the one that does not have the annoying squeal.
Ryan & Russ,
Thanks for letting me know the defective serial numbers. Really appreciate it. Still curious what is the serial numbers for the good quality ones.
Hi everyone, I’m having the same problem with my new Seasonic x-650. I found this page after doing a google search and was disheartened to find out this is a common problem which a product which I had thought was top of the line.
I just sent an email to Seasonic so fingers crossed they’ll be helpful.
My S/N is: R1009BA190550043
*with a product
Thanks for this post, Ryan. I’m in a bad state with my pc, and a new PSU was looking to be the answer. Just before I rushed out to get this very model of seasonic I saw your post. Thanks alot!
Coil noise is driving me absolutely insane. It’s not actually very loud coming out of my psu, but it’s transmitted through my firewire audio interface and amplified by my speakers. Hence, looking for a power supply with the least reported coil noise I can find.