imac 2021 buzzing noise

i'm not fortunate enough to have anything M1, but i'm pretty sure that with only flash storage in them it shouldn't be making any noise. my intel iMac 19,1 is 100% flash storage and it runs absolutely silent. i'm positive that you should be Contacting Apple for support and service. buzzing noises are very likely abnormal.

Tried increasing the brightness and yes, the noise goes away, the moment the brightness is reduced again, it starts right back.

I've had my M1 iMac for a few days and I can confirm than mine whines too. I'm certain all do to some extent. It bothers me a little but I mostly notice at night, or if it's really quiet during the day but not always. Funnily, only certain brightness clicks triggers it. Maybe it doesn't whine at 7 clicks, then whines at 8, then stops at 9 for example. I can live with mine because I think it's a mild case. I can see for louder ones an exchange is necessary. But I also think it's useless to have it exchanged now if the whine is faint, because until Apple changes something it's very probable that a new will whine even worse. So better stick with good enough for now.

It could be what is known as "coil whine" which from what I'm reading is normal for electronics and the noise can get quieter over time or disappear altogether.

Two weeks in I do notice it less now—not sure if it did in fact get better or if I'm not as bothered by it. I also turned off "Adjust brightness Automatically" as I found myself not needing it with my desktop environment.

Hi,

thank you for sharing your experience. Guess i have the same kind of problem. just want to ask if your problem can compare to mine?

I've also got the M1 iMac, so I hear a buzzing sound and also can locate it, if I put my ear direct over the ports (behind the screen) iam pretty sure that is the spot where the sounds come from ... so what I have figured out, when I lower the brightness to 85% and below, then you can hear the buzzing sound, but when iam at max brightness it is dead silent.

until now I did not change the power cable position. will going for that.

my response above that the new iMac should not be making noise was recommended by apple. if you are hearing noise, buzzing or otherwise, please get a hold of apple ASAP. it is not normal.

Contacting Apple for support and service

I have the same issue on iMac M1 (8 Core GPU) and it is driving me crazy. My apartment is very quite and I stay up late at night, which makes the sound even more noticeable. First I thought it was the fan but now I think it is the electronic circuit making humming / hissing sound. The sound seems to be coming from the bottom of the screen, the chin, towards the centre and that's where the logic board is. It starts as the Mac is turned on and is only masked if the speakers are in use, otherwise it does not stop till Sleep / Shutdown.

That’s exactly my case. It’s like a mosquito and it drives my totally crazy (in the silence of my room, mainly at night). I’m almost sure it’s caused by the LCD inverter. A solution could be installing a little app which reduces the brightness of the display (leaving the brightness bar at the maximun in the Mac settings) but I’m not gonna spend this amount of money on a faulty Apple device! Today I’m gonna give it back to the Store…

Indeed! It is very frustrating, specially when you spend that much coin on a new machine. I’ll contact Apple support as soon as I can but since Melbourne is in Lockdown again, I guess I’ll have to wait for another week.

Disabled Ethernet but that did not make any difference. I have found a temporary fix but it is not the ultimate solution. By disabling auto brightness and increasing brightness level to about 75-80%, the noise goes away. It will keep the display at fixed brightness but at least I don't have to listen to those annoying sounds anymore till I can get in touch with Apple.

Hmm. Wonder if the problem occurs with the base iMac that doesn’t come with Ethernet. Anybody? Either way, a troubling start to an otherwise grand machine. Let’s hope the fix is something trivial. Good luck!

Same problem here. At full brightness no noise, but <60% it is here and changing by changing the brightness. LCD inverter is indeed probably the problem. I will not have this noise around myself for the rest of the lifetime of the iMac!