Recent 27" iMacs are NOT silent

[motrek]

Last night I was on my iMac, it was late so I didn't have any music playing and the road was quiet outside. The fan noise was a little intrusive. So I had a little play around with setting it to 1000rpm which did help. The Mac fan control app is good but doesn't allow you to set a fan curve which isn't ideal. This means the fan would ramp up with the fluctuations in temp.

Yes, Macs Fan Control seems like a good program but I wish it would 1) allow you to base the fan speed on the CPU PECI and the GPU diode, whichever is higher, and 2) smooth out the changes to the fan speed. I've written the developers and it sounds like both features are on the radar but there's no ETA yet.

That being said, I don't know your workload, but I'm surprised your fan is spinning up much. The base model 2019 5K iMac's CPU has a TDP of 65W whereas mine has a TDP of 95W, and it takes my iMac about 20-25 seconds of being run at 100% before the CPU PECI temperature gets to 70. But, maybe you do that sort of thing often.

Interestingly the system default for the fan keeps the fan almost always at 1200rmp even when the CPU temp hits high 70s.

Yes, I have configured Macs Fan Control to start at 70 and max out at 90. I feel like that's much more aggressive than Apple's algorithm, which I consider a good thing. Although I do understand that these CPUs are designed to run indefinitely at around 100C.

I've pretty much explored all other options within Apple and have to conclude there is no perfect solution. I had a 2018 Mac mini connected to the new 23.7" LG Ultrafine, and the iGPU was woeful. I tried the 13 MBP connected to the same monitor, the fans were constantly on at a level I wasn't comfortable with. The iMac has a constant 1200rpm fan even though it's capable of running at 1000rpm. I could stretch to the 16 MBP but I wouldn't have enough budget for the AppleCare and don't need portability.

Right. It's pretty dumb if you are dead-set on a high-DPI display. If not, any Mac made in the last ~8 years will have no problem whatsoever driving a 1440p display.
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This thread could run forever but I doubt Apple will do anything about this so called 'noise issue' when it only affects a miniscule number of Mac users worldwide (I haven't seen anything that would lead me to believe the contrary). Therefore I think the only option for those who can't put up with it is to source a different type of computer.

The point isn't so much to get Apple to issue a fix to the firmware, but rather give balanced information about how much noise you can expect from these computers, for people considering a purchase. The fact is that you don't really know how many users are bothered by the noise from their iMac, or how many would appreciate it if their iMac was quieter.

This thread already has a number of contributors who returned iMacs because they were too loud for their tastes, and other threads have similar stories. Of course, it's a self-selecting group, no big surprise for a thread entitled "iMacs are NOT silent," but still, what are the odds that only this handful of people has been annoyed...

 

[Wolf1701]

I have tryed the 1000 rpm trick on my iMac 2019, really a game changer... I figure that I will use it in a 'only when really needed' basis, just to stay safe.

kudos to everyone who has tested it and reported they results here.

 

[LiE_]

I have tryed the 1000 rpm trick on my iMac 2019, really a game changer... I figure that I will use it in a 'only when really needed' basis, just to stay safe.

kudos to everyone who has tested it and reported they results here.

Yea it's a good way to look at it, because for me I don't use my iMac in silence 95% of the time. For the other 5% a quick command and it's running much quieter.

I assume it resets for you on reboot?

I don't think there is any risk to this approach, as long as you aren't running constant 1000rpm.

Like I mentioned above the only downside to using Macs Fan Control is that you have no control over how it ramps up the fans so depending on your workload using the app may result in a noisier fan. By default when I'm in Lightroom and Photoshop the fan stays at 1200rpm, but running this app it can can ramp up 1550rpm when I'm using sliders a lot.

 

[motrek]

I have tryed the 1000 rpm trick on my iMac 2019, really a game changer... I figure that I will use it in a 'only when really needed' basis, just to stay safe.

kudos to everyone who has tested it and reported they results here.

I guess you have to be familiar with your workload. Nothing I do stresses the GPU, so if I configure the fan to spin up based on the CPU PECI temperature then I think I should be covered. And I believe that any remotely modern chip will slow down and then shut off before any permanent damage is done from overheating. So even if something goes wrong and the GPU heats up without the fan spinning up, I'm pretty confident that I wouldn't do lasting damage to my iMac.

If anything, I feel a little better that my fan will max out when the CPU gets to 90C, unlike Apple's algorithm, which seems perfectly content to let the CPU temperature reach the mid or high 90s and only spins the fan up to ~2400 at those temperatures. :/
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I assume it resets for you on reboot?
...

The first couple times my iMac woke from sleep, I could swear that the fan speed was reset to 1200, but it hasn't happened since then so maybe it was my imagination. I can't remember if my setting survives a reboot, but I put it in a script anyway so it just takes a second to run that script... (Force-quit Macs Fan Control, set the minimum fan speed, restart Macs Fan Control...)

 

[1204949]

I gave it another try and this time bought a used iMac 2017, 27" with the infamous i7 7700K.

On the positive side: It's much more silent during idle than were the two 2019 27" iMacs I had bought new and returned. I can barely hear it anymore and there is no whine either. Still a bit more present than my 21.5" iMac but this is a big relief.

However this thing gets hot very quickly. Once under full load it permanently stays at a tad below 100°C and the fans spin up to their max. 2700 rpm. No throttling though, the machine runs just fine. I'll keep this machine though because I only every use burst power and idle noise is much more important to me.

In essence: Three iMacs - all of them showing a different behavior during idle even though they were all set to run at their minimum of 1200 rpm.

 

[LiE_]

A used iMac may be full of dust at this point reducing its cooling efficiency.

 

[1204949]

A used iMac may be full of dust at this point reducing its cooling efficiency.

Well, I checked the air intakes and you were right. It's full of dust.

I carefully cleaned it using a tiny brush and a vacuum cleaner and now the idle temperatures have dropped by around 6°C to roughly 36°C. Under load (4.xGhz, all core) it still ramps up to 2700 rpm but it takes much longer to do so and the temperatures stay at around 95°C. A few degrees "cooler" than before.

Guess to really get the temperatures into a healthy range this machine would need to be opened completely, cleaned and then repasted with TIM. Maybe even swap out the CPU to an i5 7600K or an i7 7700 non-K.

 

[cannondale1974]

Just bought a new 2019 27" iMac, i9 SSD. Compared to my 2010 27" iMac with i7 and old spinning HD, it's absolutely silent. Old iMac makes noises all the time, never really that disrupting but it's definitely not quiet. The old iMac also gets MUCH, MUCH hotter when doing intensive tasks, rendering etc.

 

[Wolf1701]

Yea it's a good way to look at it, because for me I don't use my iMac in silence 95% of the time. For the other 5% a quick command and it's running much quieter.

I assume it resets for you on reboot?

I don't think there is any risk to this approach, as long as you aren't running constant 1000rpm.

Like I mentioned above the only downside to using Macs Fan Control is that you have no control over how it ramps up the fans so depending on your workload using the app may result in a noisier fan. By default when I'm in Lightroom and Photoshop the fan stays at 1200rpm, but running this app it can can ramp up 1550rpm when I'm using sliders a lot.

Yes, on reboot (power off, power on) the value reset itself to 1200. (smc -f and/or another fan monitor app can confirm that).

I find this behavior comforting, you can't really damage nothing on the smc, the only risk is from overheating. To avoid this I set Mac fan on CPU proximity, this will keep an eye on both cpu and gpu temp.

Better safe than sorry if the fan ramp up, enjoy the silence when you can

 

[motrek]

Yes, on reboot (power off, power on) the value reset itself to 1200. (smc -f and/or another fan monitor app can confirm that).

I find this behavior comforting, you can't really damage nothing on the smc, the only risk is from overheating. To avoid this I set Mac fan on CPU proximity, this will keep an eye on both cpu and gpu temp.

Better safe than sorry if the fan ramp up, enjoy the silence when you can

Ooh, I would NOT use CPU proximity.

I don't know where that sensor is, but when I was doing some experimenting to decide how to set up Macs, it seemed like the CPU proximity reading was usually dramatically lower than the CPU PECI reading and also lagged any increases by a long time. Like, sometimes more than a minute.

CPU PECI is the sensor that Intel intended specifically to control CPU fan speed (check it out on Wikipedia) so you should really just use that.

Also, if you look at a teardown of a 5k iMac, the CPU and GPU are not very close to each other, maybe like 6" apart (eyeballing), so if you control the fan speed based on CPU proximity, I don't think that really accounts for the GPU temperature at all.

If you're really worried about the GPU overheating, there should be some consolation that the CPU and GPU are connected to the same heatsink, so if the GPU gets hot then the CPU will also get hot, at least to some degree... on top of the consolation that I'm pretty sure that the GPU will shut down before it overheats and gets damaged.

Ultimately it would definitely be really nice if Macs let you control the fan speed based on the higher of two readings though.

 

[Wolf1701]

If you're really worried about the GPU overheating, there should be some consolation that the CPU and GPU are connected to the same heatsink, so if the GPU gets hot then the CPU will also get hot, at least to some degree... on top of the consolation that I'm pretty sure that the GPU will shut down before it overheats and gets damaged.

Ultimately it would definitely be really nice if Macs let you control the fan speed based on the higher of two readings though.

I assume that cpu proximity is the cpu (and gpu, I am sure, tested) heatsink. I am not worried about cpu temp, the cpu will surely shut down if overheating, gpu in iMac are instead historically more... delicate. I am more concerned about the global temperature inside the case to prevent some long term damage to the other electronic parts (Mainboard components, screen).

 

[ondert]

Can you tell me how loud/silent the base 2019 5K model is? I’ve sold my 2017 5K before I moved abroad to avoid the hussle and price of carrying in plane. Now, I need an iMac again, and the second hand market prices are ridiculously high here that buying a brand new one with student discount makes more sense although I prefer to wait for next gen.

 

[LiE_]

Can you tell me how loud/silent the base 2019 5K model is? I’ve sold my 2017 5K before I moved abroad to avoid the hussle and price of carrying in plane. Now, I need an iMac again, and the second hand market prices are ridiculously high here that buying a brand new one with student discount makes more sense.

It’s audible in a quiet room. Like a constant low noise.

 

[motrek]

I assume that cpu proximity is the cpu (and gpu, I am sure, tested) heatsink. I am not worried about cpu temp, the cpu will surely shut down if overheating, gpu in iMac are instead historically more... delicate. I am more concerned about the global temperature inside the case to prevent some long term damage to the other electronic parts (Mainboard components, screen).

Unfortunately I'm not at my iMac now so I can't do any experimenting myself but I'd suggest you double-check your measurements re: the CPU proximity sensor. Modern CPUs can get very hot very fast and would ideally be cooled when that happens. I remember putting the CPU in my iMac under load and the CPU PECI temperature would increase 30+ degrees within a few seconds whereas the CPU proximity temperature barely moved.

Also I remember doing one test where I stressed the GPU and I don't recall the CPU proximity temperature changing much.

If you do any further experiments, I'd be interested if you posted the results.

As for the mainboard components and screen becoming damaged, that was also a concern of mine, but my thinking is that the CPU and GPU are the only parts in the computer that can produce any significant amount of heat, so if you have your fan control set based on those components then you should be set re: the other components.

 

[Lankyman]

Can you tell me how loud/silent the base 2019 5K model is? I’ve sold my 2017 5K before I moved abroad to avoid the hussle and price of carrying in plane. Now, I need an iMac again, and the second hand market prices are ridiculously high here that buying a brand new one with student discount makes more sense although I prefer to wait for next gen.

I suppose it depends on your hearing and is subjective anyway. I can hear nothing myself. My wife whose hearing is bat like can also hear nothing.

 

[motrek]

I suppose it depends on your hearing and is subjective anyway. I can hear nothing myself. My wife whose hearing is bat like can also hear nothing.

Dude, I mean, you've already said you have a NAS in the same room as your iMac which masks any sound the iMac might make, so I don't know why you think it's of any use to anybody to tell us that you (or your wife) can't hear your iMac.

I can't hear my iMac either, if I'm wearing earplugs and standing in a different room, but you don't hear me telling that to other people as if it's an interesting fact.

 

[Lankyman]

Dude, I mean, you've already said you have a NAS in the same room as your iMac which masks any sound the iMac might make, so I don't know why you think it's of any use to anybody to tell us that you (or your wife) can't hear your iMac.

I can't hear my iMac either, if I'm wearing earplugs and standing in a different room, but you don't hear me telling that to other people as if it's an interesting fact.

Please! credit me with some intelligence. I shut the NAS down to conduct the test and as we live on the edge of the countryside our property is as quiet as the grave. Believe me if my wife says she can’t hear something then whatever it is will be pretty much silent, so YES I believe my input into this debate is as valid as anyone else’s.

 

[motrek]

Please! credit me with some intelligence. I shut the NAS down to conduct the test and as we live on the edge of the countryside our property is as quiet as the grave. Believe me if my wife says she can’t hear something then whatever it is will be pretty much silent, so YES I believe my input into this debate is as valid as anyone else’s.

Dunno man. It seems like basically everybody else on this thread can hear their 5K iMacs; even the people who are happy with how quiet they are admit that they make some audible noise. Which they objectively do.

If you're in a location with minimal ambient noise, and your wife has perfect hearing, and she literally can't hear anything from your iMac, then I guess the fan is broken and you should probably take the machine to an Apple Store to get it fixed before it melts. Because there's no other explanation for what you're posting.

EDIT: Another thing is, how did you test your wife? If all you did was ask if she could hear the iMac, that's hopelessly flawed. She probably doesn't know what she's listening for, and/or isn't super-familiar with how that room sounds without the iMac running, so how would she know if she could hear it or not. The only legit test I can think of is to do the hack to lower the minimum fan speed to 1000 RPM, then use Macs Fan Control to vary the fan speed back and forth between 1000 and 1200 RPM. If you can't hear that difference in a quiet environment then I think your hearing must really be awful.

 

[Lankyman]

Dunno man. It seems like basically everybody else on this thread can hear their 5K iMacs; even the people who are happy with how quiet they are admit that they make some audible noise. Which they objectively do.

If you're in a location with minimal ambient noise, and your wife has perfect hearing, and she literally can't hear anything from your iMac, then I guess the fan is broken and you should probably take the machine to an Apple Store to get it fixed before it melts. Because there's no other explanation for what you're posting.

EDIT: Another thing is, how did you test your wife? If all you did was ask if she could hear the iMac, that's hopelessly flawed. She probably doesn't know what she's listening for, and/or isn't super-familiar with how that room sounds without the iMac running, so how would she know if she could hear it or not. The only legit test I can think of is to do the hack to lower the minimum fan speed to 1000 RPM, then use Macs Fan Control to vary the fan speed back and forth between 1000 and 1200 RPM. If you can't hear that difference in a quiet environment then I think your hearing must really be awful.

It appears your knowledge of auditory range is somewhat lacking. As one gets older a general rule of thumb is that the higher auditory range diminishes but the lower range remains good e.g. bass sounds. It may well be that many of the posters on this thread are sensitive to the auditory range the fan is emitting. It may be that I nor my wife are not.
This doesn’t mean the iMac is noisy rather those who are complaining are sensitive to the fans frequency. Therefore I am lucky in that for me my iMac is almost silent.

 

[LiE_]

Anyone used TG pro to create a custom fan curve for the iMac?

TG Pro

Maximize your Mac's performance with TG Pro. The ultimate solution for fan control and extensive temperature monitoring: CPU, GPU, SSD, and more.

www.tunabellysoftware.com

 

[motrek]

Anyone used TG pro to create a custom fan curve for the iMac?

I won't be able to try this for a while but it looks promising re: being able to speed up the fan if either CPU PECI is high or the GPU diode is high. If you try it, could you report back? Thanks in advance.

 

[LiE_]

I've downloaded it but I don't think the fan settings apply in the trial. I'm reluctant to pay for it until I'm sure it's good for what I want.

 

[zerozoneice]

it's not only the cpu that gets hot and needs cooling, but also the gpu.
since imac 2019 has only one fan, it has to cool both.
the 580X imac is the loudest (under gpu load: benchmarks, gaming, bootcamp games) i have ever heard.
didn't have a vega 48 but i can imagine it's pretty close.

My old M395 unit was whisper quiet under load compared to this one.

Current imac (thermal) design is reaching its limits. Next imacs should have at least the imac pro cooling system, if not a total redesign.

 

[Lankyman]

it's not only the cpu that gets hot and needs cooling, but also the gpu.
since imac 2019 has only one fan, it has to cool both.
the 580X imac is the loudest (under gpu load: benchmarks, gaming, bootcamp games) i have ever heard.
didn't have a vega 48 but i can imagine it's pretty close.

My old M395 unit was whisper quiet under load compared to this one.

Current imac (thermal) design is reaching its limits. Next imacs should have at least the imac pro cooling system, if not a total redesign.

But for those of us that don't benchmark, play games or use Bootcamp, (probably the majority) this machine remains whisper quiet. IMO

 

[motrek]

it's not only the cpu that gets hot and needs cooling, but also the gpu.
since imac 2019 has only one fan, it has to cool both.
the 580X imac is the loudest (under gpu load: benchmarks, gaming, bootcamp games) i have ever heard.
didn't have a vega 48 but i can imagine it's pretty close.

My old M395 unit was whisper quiet under load compared to this one.

Current imac (thermal) design is reaching its limits. Next imacs should have at least the imac pro cooling system, if not a total redesign.

Mine has a 6700K and M395X. Either one under sustained load can cause the fan to spin up to almost maximum speed in about a minute. The sound from the fan at max speed doesn't have an unpleasant character but it sure is loud. I would be extremely unhappy if I had to use my iMac for sustained processing. As is, it's only under load for maybe 20-30 seconds at a time, max. Otherwise I think I would need to buy something else, like a trash can Mac Pro, or probably just a PC running Linux that I could use from my iMac.