Cooling in the new 2020 27" iMac?

[assisterah]

keep in mind that the ambient temperature plays a role in this situation. If you live in a humid environment especially during hot summer times, a “silent” idle iMac’s fan would ramp up and you would hear it.

Coming from a Mac Pro and customized water cooling pc I am sensitive to the noise. Unless you have complete fan control like on my pc or a vastly superior air cooling capacity like Mac Pro 7,1 you will hear the noise at some point especially under load. The iMac’s cooling is simply not there to keep the machine quiet at all times.

I’m currently waiting for my iMac 2020 to arrive and will test and see. If it keeps silent at idle I will probably keep it. I don’t expect it to be silent under heavy load but if it cannot keep quiet at idle,I would return it too.

 

[quagmire]

keep in mind that the ambient temperature plays a role in this situation. If you live in a humid environment especially during hot summer times, a “silent” idle iMac’s fan would ramp up and you would hear it.

Coming from a Mac Pro and customized water cooling pc I am sensitive to the noise. Unless you have complete fan control like on my pc or a vastly superior air cooling capacity like Mac Pro 7,1 you will hear the noise at some point especially under load. The iMac’s cooling is simply not there to keep the machine quiet at all times.

I’m currently waiting for my iMac 2020 to arrive and will test and see. If it keeps silent at idle I will probably keep it. I don’t expect it to be silent under heavy load but if it cannot keep quiet at idle,I would return it too.

I think some are saying they can hear it even when the fan is at 1200 RPM which is the idle speed for the fan. Not that they are hearing the fan ramp up.

That is the case for me as I said in my post last page. I can hear the fan at 1200 RPM if it is the only source of white noise in the room in both my 2013 and 2019.

 

[costica1234]

Sorry to hear this. I have a 2020 27-inch i7. I work in a fairly quiet environment and sit about 20 inches away from the screen. During the day I can't hear the fan, given the slight ambient noise. When I'm working at night it becomes barely audible, but I have to listen for it. I do notice what I would describe as a subtle "flutter" when the fan starts up after waking from sleep (an audible muffled clicking). It lasts only briefly while the fan spins up to 1200RPM. Do you experience this also?

Would you be able to use a dB meter app and measure the noise level in your room when the iMac is on (at idle) and when it's off? I did this test with my mid-2015 15'' MBP and got 24-25 dB with the laptop OFF (I have a quiet room as well), and then 30-31 dB with the laptop ON at IDLE speed (note that I placed the bottom of my iPhone towards the charging port in order to pick up the noise).

This seems to be in line with the sound pressure level shown on Apple's wesite which is at 6 dB for my specific MBP. Since the 2020 iMac has a sound pressure (w.r.t. operator position) of 13 dB, I would probably get an extra 7 dB compared to the MBP (at idle speed). Unfortunately, those extra dB do make a difference and you don't really need to have sensitive hearing to pick it up. Even my mom was able to tell the difference between 30 dB and 37 dB when I increased the fan speed.

I was really keen on getting the 2020 iMac, but this issue is really putting me off at the minute.

 

[pldelisle]

I cannot see why so many people want it to be such silent.

It’s a computer. A powerful computer. With subpar cooling system (everybody on earth knows this). But still, it’s a computer. This thing dissipate energy, heats, and is cooled by fan,just like any powerful normal computer in the world.

Yeah it’s normal to want it to be quiet at idle. But *silent* at idle?

People either don’t understand the law of physics or expectations are way too high.

Or might be because I’m sitting 12-14h a day next to a 13-fan dual GPU workstation and I’m used to it. But hey, this WS is *powerful* at crunching numbers. So I don’t care since it gets the job done. I think this should be the attitude people should adopt with this iMac.

 

[yellow_lupine]

I'd like to remember to anyone concerned about fan noise that you have 14 days to fully test the iMac before keeping or returning it. Since noise is strictly subjective it would be better if you could verify yourself.

I had the opportunity to try the latest 2020 iMac (10-core, 5700XT) and took a measurement of the produced noise sitting in front of it at normal operating position (about 18" from the computer) in a small room with very low noise: at idle it was 26 dBA; at mid load 30 dBA and at max load 42 dBA.

All depends on your usage.

 

[mlykke]

I'd like to remember to anyone concerned about fan noise that you have 14 days to fully test the iMac before keeping or returning it. Since noise is strictly subjective it would be better if you could verify yourself.

I had the opportunity to try the latest 2020 iMac (10-core, 5700XT) and took a measurement of the produced noise sitting in front of it at normal operating position (about 18" from the computer) in a small room with very low noise: at idle it was 26 dBA; at mid load 30 dBA and at max load 42 dBA.

All depends on your usage.

Exactly - It's so subjective that everybody has to make up their own mind.

Glad to read that you're actually doing db testing correct instead of just jamming the db meter directly to the source of the noise. You have to measure that stuff from where you would be located. It doesn't matter if something makes a 100db of noise if you are located 10km away.

40db is the sound of a quiet library. The noise levels seem to be more than fine.

https://audiology-web.s3.amazonaws.com/migrated/NoiseChart_Poster-%208.5x11.pdf_5399b289427535.32730330.pdf

 

[edib]

I cannot see why so many people want it to be such silent.

It’s a computer. A powerful computer. With subpar cooling system (everybody on earth knows this). But still, it’s a computer. This thing dissipate energy, heats, and is cooled by fan,just like any powerful normal computer in the world.

Yeah it’s normal to want it to be quiet at idle. But *silent* at idle?

People either don’t understand the law of physics or expectations are way too high.

Or might be because I’m sitting 12-14h a day next to a 13-fan dual GPU workstation and I’m used to it. But hey, this WS is *powerful* at crunching numbers. So I don’t care since it gets the job done. I think this should be the attitude people should adopt with this iMac.

It really comes down to the actual design. Some computers are designed better than others. Take Corsair ONE i165 for example (I do appreciate that this is s completely different form factor and the fact that this is a PC, however with i9-9900K and RTX2080Ti (!!) is silent at low to medium loads and quiet at full (about 38 dB with the CPU temperature around 65C).

Here is a decent review, worth to watch just to appreciate how well it is designed.

Apple decision to keep using the same cooling design since 2012 in the iMacs while using more power demanding components is questionable at best.

 

[1229175]

Apple decision to keep using the same cooling design since 2012 in the iMacs while using more power demanding components is questionable at best.

This is precisely my issue with this 2020 27" iMac. Apple installing second fan, at the minimum, which probably would have cost them less than $10 would have been much appreciated.

 

[MBHockey]

This is precisely my issue with this 2020 27" iMac. Apple installing second fan, at the minimum, which probably would have cost them less than $10 would have been much appreciated.

Yeah, it’s clear this is a dead end product. Apple simply slapped the latest and hottest running intel CPU into the existing cooling system and while it runs within spec, it’s not an ideal cooling system for this generation CPU.

Hopefully we’ll see some changes with AS if needed.

 

[CWallace]

This is precisely my issue with this 2020 27" iMac. Apple installing second fan, at the minimum, which probably would have cost them less than $10 would have been much appreciated.

The iMac's fan vents the hot air from the CPU/GPU heat sink so a much larger fan (able to push a lot more volume) might have been a better option - especially if it could run at higher RPMs.

It also would have been easier to design and test than a dual-fan system.

 

[hazza26]

40db is the sound of a quiet library. The noise levels seem to be more than fine.

https://audiology-web.s3.amazonaws.com/migrated/NoiseChart_Poster-%208.5x11.pdf_5399b289427535.32730330.pdf

Really appreciate you getting the db meter out, first post I've seen with numbers.

18" in front of my 2009 cheese grater measures 45db. It's frickin noisy. When it's under my desk the level at my ears still reaches 36db, and it's annoying as hell. I really need a quiet machine, and based on your numbers I don't think the 2020 iMac is going to cut it.

 

[edib]

...and as I read the latest comments, the new 2020 iMac (i7, 5700 XT) just arrived at my door. It is time to find out for myself if I can live with it. My main concern is fan noise at idle while doing basic tasks and I will be comparing this with a 2017 i5 model I sold recently. (...and all the other iMacs I had since 2009).

 

[Lankyman]

At the end of the day this is a none issue as...
1. No one is making you purchase this iMac
2. If you do purchase one and find the noise to be unacceptable then return it.
We can be sure of one thing - this final Intel iMac will not be changed to accommodate those who find the noise to be an issue, no matter how much they may grumble.

 

[pldelisle]

Again, I still can't believe someone would *need* a completely silent computer. It defies the laws of physics and it's ridiculous.

 

[Darajavahus]

I'm so jealous of the people that live in such quiet places that they can hear iMac fan at 1200 RPM, and it bothers them, I suffer from misophonia, I live right next to coal mine so it's never completely quiet, cars on the road, like the wind outside exist, there is white noise coming from the tweeters of my studio monitors which is A BIT annoying, I have a big fan on nearly all the summer (I only turn it off so my ears rest, but it's so hot) that's very annoying, the most annoying is the TV other people in the house are watching, I can hear my external hard drive, but the iMac fan I never heard it in the 8 years I have it. I used istat to manually set the fan to the max to check how it sounds and it's not that bad if it would get to that at max load but it never did by itself, if you do something that you constantly have at 100% CPU or GPU then iMac may not be for you.

 

[edib]

...and as I read the latest comments, the new 2020 iMac (i7, 5700 XT) just arrived at my door. It is time to find out for myself if I can live with it. My main concern is fan noise at idle while doing basic tasks and I will be comparing this with a 2017 i5 model I sold recently. (...and all the other iMacs I had since 2009).

Ok, just connected the new iMac. The true tone display is absolutely gorgeous !
The ambient room temperature is about 19C, the case was cold when I got it out of the box (9C) outside.
CPU cores about 26C, fan at 1200rpm, quiet room 29dB or so.

Not sure what they have changed as compared with the 2017 i5 model, however the fan in the new 2020 iMac is a lot more noticeable. It goes all the time. It is just a white noise, not very loud, however [Updated wording after a few hours) it can be noticeable and somehow distracting (as it is at ears level), however it seems like it can be manageable, see below. For me [Updated wording] there is a difference between the two, so Apple claim (as per the tech sheets and in my case) that the 2020 i7 is quieter than the 2017 i5 is not very accurate.

To be honest, I am not sure why the fan needs to run at all when the CPU temperature is 25C and the CPU is using 2W.

My advise is, if are sensitive to noise and work in a quiet environment the only way to find out if the new iMac is for you is to buy one, test it and then decide. If you already have an iMac you are happy with, keep it and enjoy. Lastly, don’t sell the one you have before trying and testing the new one, you might need it.

[Update]

I have already spend a bit of time with the new 2020 iMac (i7) and have updated the wording in my original post above, toning it down a bit.

It seems like what I am hearing as compared with the old 2017 i5 iMac I had is more air movement coming out through the vents (perhaps the fan has been "upgraded" and now can push more air out as compared with the older models). When I cover the vents I hear nothing. The noise can be somehow managed, I have simply placed a pillow between my iMac and the back wall (it is close to it, same as the old one) without covering the vents and the noise quieten a bit and also its sound signature has changed. It is now closer to what I had with the old iMac. The "noise" is still there, however I wound't call it distracting or noticeable. I am now looking for some acoustics absorption panels to be installed behind the iMac, so hopefully this will help a bit more.

There is also a bit of coin whine I have discovered, however that is only audible when I place my ear very close to the right/back of the iMac. I have since reconnected the computer, powered off some nearby devices and it seems like the noise has settled a bit. In both cases I couldn't hear if from the sitting position.

Please keep in mind that all of the above comments relate to the fan at idle speed (1200 rpm) with the CPU temperature around 37C (it was 25C when I first fired it up).

Not sure if that helps anybody, however I thought that the original post needed to be updated.

 

[lcseds]

I'm so jealous of the people that live in such quiet places that they can hear iMac fan at 1200 RPM, and it bothers them, I suffer from misophonia, I live right next to coal mine so it's never completely quiet, cars on the road, like the wind outside exist, there is white noise coming from the tweeters of my studio monitors which is A BIT annoying, I have a big fan on nearly all the summer (I only turn it off so my ears rest, but it's so hot) that's very annoying, the most annoying is the TV other people in the house are watching, I can hear my external hard drive, but the iMac fan I never heard it in the 8 years I have it. I used istat to manually set the fan to the max to check how it sounds and it's not that bad if it would get to that at max load but it never did by itself, if you do something that you constantly have at 100% CPU or GPU then iMac may not be for you.

Yeah, I have Tinnitus in both ears. Either won't hear it or will consider it white noise. Different strokes for different folks. Folks that are bothered should return it. Simple as that.

 

[rkuo]

Again, I still can't believe someone would *need* a completely silent computer. It defies the laws of physics and it's ridiculous.

It's an interesting build challenge for sure. It's not completely ridiculous if you've engineered your workspace to be at some level of quiet ... however, it's also not the kind of thing anyone should expect a mass market device like the iMac to cater to. This stuff is in the realm of custom builds or expensive additional hardware.

Honestly, in my opinion, this kind of silence is best accomplished having some thunderbolt cables run through a wall to a computer on the other side.

 

[RAWvJPG]

Again, I still can't believe someone would *need* a completely silent computer. It defies the laws of physics and it's ridiculous.

Never heard of that law of physics before.

Assuming you sit in front of your iMac at working distance it is perfectly possible to have a computer that is completely silent at idle. My old PCs that I've built were, so is my current MacBook Pro 13" 2019, my old iMac 21.5" 2017 and the MacMini 2018 as well. For some strange reason however, the iMac 27" models are not.

No law of physics being defied here. Just Apple's engineering disenchanted.

 

[RAWvJPG]

Ok, just connected the new iMac. The true tone display is absolutely gorgeous !
The ambient room temperature is about 19C, the case was cold when I got it out of the box (9C) outside.
CPU cores about 26C, fan at 1200rpm, quiet room 29dB or so.

Could you please run Cinenbech and report on the fan speed?

 

[RAWvJPG]

Yeah, I have Tinnitus in both ears. Either won't hear it or will consider it white noise. Different strokes for different folks. Folks that are bothered should return it. Simple as that.

Well, but what should these folks buy instead? If you are stuck with MacOS and Apple is reluctant to fix their flawed cooling than all you can do is wait for the next iteration, whenever that comes.

 

[pldelisle]

Never heard of that law of physics before.

Assuming you sit in front of your iMac at working distance it is perfectly possible to have a computer that is completely silent at idle. My old PCs that I've built were, so is my current MacBook Pro 13" 2019, my old iMac 21.5" 2017 and the MacMini 2018 as well. For some strange reason however, the iMac 27" models are not.

No law of physics being defied here. Just Apple's engineering disenchanted.

They all have a fan in them.

I've been a long time in hardware. "Silent" means fanless. Nothing less.

Having such power and being fanless is ridiculous and defies law of physics for such a small case. It needs active cooling.

MacMini has 6 cores. You 2017 iMac probably has 4 cores. This current iMac has 8 or 10 cores and is still on the same fabrication node than all those previous generation CPUs. It will dissipate more heat. You will need higher speed fan/more frequently fan speed ramping up to keep it cool.

iMac Pro had enough cooling, but needed it to sport up to 18 cores Xeon, which obviously has higher TDP than this 10 core has. And it lost user upgradable RAM. I agree this would have been perfect cooling for the normal iMac and probably quieter than the current cooling system, but to criticize to the point of returning it because you hear it on idle, there's a problem not from the computer, but from the user.

 

[LiE_]

I've been a long time in hardware. "Silent" means fanless. Nothing less.

When I build my custom PCs, you cannot hear those. Noctua fans running at 500 RPM are silent.

Additionally, fans don't need to run a lot of the time. My Lenovo Thinkpad 13 I'm using right now with an i5, the fans aren't running while I'm typing this. Most modern GPUs have a zero RPM mode as well when they are being taxed.

This is my last build, you cannot hear it even sat on my desk, even with 7 fans. Because they are running slow.

 

[pldelisle]

When I build my custom PCs, you cannot hear those. Noctua fans running at 500 RPM are silent.

Additionally, fans don't need to run a lot of the time. My Lenovo Thinkpad 13 I'm using right now with an i5, the fans aren't running while I'm typing this. Most modern GPUs have a zero RPM mode as well when they are being taxed.

This is my last build, you cannot hear it even sat on my desk, even with 7 fans. Because they are running slow.

It's a custom gaming PC. Not an AiO form factor. Your heat dissipation capacity is WAY higher than what's possible for any AiO that exists. Plus you use water-cooling.

The CPU in your laptop is probably an ULV. So mostly a 15w TDP CPU, compared to a 95W-125W in a desktop. It can probably be fanless when idling, consuming only a few watts.

I personally don't use water-cooling in my workstation. In my case, all my Noctua fans need to run at full speed 24/7. Because that thing heats more than probably any PC you've heard for.

 

[DRuser]

Not sure what they have changed as compared with the 2017 i5 model, however the fan in the new 2020 iMac is a lot more noticeable.

Thanks for sharing your experience. I'd love to see a comparison to the 6 core model, as I don't need the extra power of the 10 cores.