Fan noise on iMac 2020

[triton100]

Now that it has finished the indexing etc that a Mac does when it is new, I have to try hard to hear my i7/5700 when idle. What I mean is that I have to put my ear right up to it to hear anything. The fan does spin up when the machine is pushed, even moderately, but I wouldn’t call it obtrusive. Of course everyone’s tolerance for these things is different, and it certainly isn’t silent.

I have no experience with the i9/5700XT so cant compare.

What is the noise in decibles ? Yiu can use the iPhone to measure the loudness

 

[shhh2020]

…some of the folks on here are shocked that the fan comes on…

Not shocked about that all. Just wondering if it should be as "dead silent" as any usual MacBook Pro for example which are exactly that, dead silent when doing simple tasks like a bit of browsing or writing up emails. If the iMac is not supposed to be THAT silent while doing easy stuff, everything is fine. I myself was just wondering a) if it should be as silent as a MacBook Pro and b) if there are some models that actually are and others that are not…

 

[wilberforce]

What is the noise in decibles ? Yiu can use the iPhone to measure the loudness

The problem with measuring the decibels, is that it depends on exactly where and how far from the vent you measure the noise.
I measured the loudness using my Apple watch (which I don't think is very accurate) near the round hole in the back of the iMac stand, and my 2020 iMac measured about 2dB louder than my 2014 iMac, both running at 1200 rpm. (2020 iMac ~35dB, 2014 iMac ~33 dB, room ambient baseline ~31 dB)

My 2020 iMac I can just barely hear from a sitting position in a quiet room. My 2014 iMac was inaudible to me at a sitting position (both running at idle 1200 rpm).
The issue appears to be that different 2020 iMacs appear to have different sounding fans, with no consistency. That combined with different people having different sensitivity and/or different ambient environments, makes it impossible to predict whether it will be acceptable to an individual or not.

 

[triton100]

The problem with measuring the decibels, is that it depends on exactly where and how far from the vent you measure the noise.
I measured the loudness using my Apple watch (which I don't think is very accurate) near the round hole in the back of the iMac stand, and my 2020 iMac measured about 2dB louder than my 2014 iMac, both running at 1200 rpm. (2020 iMac ~35dB, 2014 iMac ~33 dB, room ambient baseline ~31 dB)

My 2020 iMac I can just barely hear from a sitting position in a quiet room. My 2014 iMac was inaudible to me at a sitting position (both running at idle 1200 rpm).
The issue appears to be that different 2020 iMacs appear to have different sounding fans, with no consistency. That combined with different people having different sensitivity and/or different ambient environments, makes it impossible to predict whether it will be acceptable to an individual or not.

Thanks. That reading is at idle? That’s quiet. And I’m sensitive for sure. I’m more wary about the loudness when the cpu is hitting around 75 percent. I always measure from just in front of the computer as that’s where the fan noise will be coming from. For me, experience has dictated that anything over say 42dbs starts to annoy me. I can handle anything under that. For comparison MacBook Pro 16 full speed fans hit 54dbs.

 

[wilberforce]

Thanks. That reading is at idle? That’s quiet. And I’m sensitive for sure. I’m more wary about the loudness when the cpu is hitting around 75 percent. I always measure from just in front of the computer as that’s where the fan noise will be coming from. For me, experience has dictated that anything over say 42dbs starts to annoy me. I can handle anything under that. For comparison MacBook Pro 16 full speed fans hit 54dbs.

Yes, those readings were at idle.
Using Macs Fan Control to force the fan to run at full blast (2700 rpm), I measure 60dB on my watch at the round hole in the back of the stand. From my sitting position it measures 43 dB at 2700 rpm. But the noise at your sitting position will greatly depend on the acoustics of the surrounding walls reflecting the noise. My iMac has no surrounding walls nearby, so the noise dissipates easily.
Again, I think it is impossible to predict what will be acceptable to an individual in their individual environment. Another thing is the quality of the noise (frequency distribution). Loudness reading is only measuring sound pressure.

 

[triton100]

Yes, those readings were at idle.
Using Macs Fan Control to force the fan to run at full blast (2700 rpm), I measure 60dB on my watch at the round hole in the back of the stand. From my sitting position it measures 43 dB at 2700 rpm. But the noise at your sitting position will greatly depend on the acoustics of the surrounding walls reflecting the noise. My iMac has no surrounding walls nearby, so the noise dissipates easily.
Again, I think it is impossible to predict what will be acceptable to an individual in their individual environment. Another thing is the quality of the noise (frequency distribution). Loudness reading is only measuring sound pressure.

Thanks for that info. And yes you’re right on all points. I’m so torn as to whether to go for the iMac which suits my needs v well or whether to pony up a lot more for a completely silent Mac Pro.

 

[wilberforce]

Thanks for that info. And yes you’re right on all points. I’m so torn as to whether to go for the iMac which suits my needs v well or whether to pony up a lot more for a completely silent Mac Pro.

This is exactly the purpose of the 14 day return period, no questions asked, no guilt required

 

[arkviz]

I just got i7 8-core 5700XT and it is dead silent on idle, but VERY Loud when continuous CPU usage exceeds 100% (Maximum is 1600%+ 16 threads). Performace is also dropping and numbers I saw on MaxTech YouTube video test are not reachable. Cinebench R20 scores about 4200 together with mind paralyzing noise. Since I work on 3D, it is annoyng and this iMac is for me useless. If it wasn't so expensive, I'd throw it out of window. I still make 3D on Mac Pro 5,1 which scores 3000 but it is quiet. On real projects, due to thermal throtling, iMac doesn't render any faster than this 11 years old dinosaur.

 

[RoryOz]

Moved from a base iMac pro (8 core xeon, 32gb ram,vega 56, 1tb hd) to a 2020 iMac i9 (10 core 64gb ram, 2tb Hd, Radeon 5500 xt).

Main use: Audio recording, editing, mixing on Cubase.

Had my Imac pro for over 2.5 years and only once heard the fans ramp up and it was not even cubase related, it was while gaming on max graphic setting (I don't usually game on an iMac).

The iMac pro NEVER ramped up the fans on audio editing regardless of how much CPU consuming the task was, even in the end of projects with all the vsts etc.

On the iMac 2020 the fan is WAY louder towards the end of a project or even if the room has no ac on.

This is quite annoying because I am dealing with audio here, I need complete silence in my studio otherwise the fan noise interferes with my listening experience or recording procedure.

All in all, i guess it was a bad decision selling my iMac pro, I guess I just listened to all those YouTube videos stating the new iMac is WAY more powerful than the iMac pro when in real life audio editing I see no difference.

This is a video I captured after working for about 10 min on a rather heavy project in cubase 10.5.
As you can see from istat menus and fan apps: the cpu is not even at 50%, the ram is not even on 50%, I have got around 750gb free on my 2tb nvme drive, so I belive the issue drivfes form the graphics card?

As you can see the GPUshoes no signsstruggle in its cpu but for some reason its ram is almost 100% I belive that this might be the issue here.

Do you have any idea on WHYthis is happing?
Is it side car on my iPad pro 12.9 2020? (I use it via cable)
Isthere something in cubase using so much GPU ram?!

 

[no_fan_my_ass]

5700XT i7 here. At idle (1200rpm) I can hear the fan from over an arms length away. It is definitely not silent.

If it's useful to anyone:

With the iPhone app "Decibel X" on my desk directly in front of me with the bottom pointing towards my iMac, the 10 second average is 27.5.

With the iPhone leaning up against the chin of the iMac (visa mounted) with the bottom pointing towards my iMac (upwards), the 10 second average is 28.4.

To add, at idle I'm at 58-59c.

I am running a 4K external monitor over USBC, and a 10.5 iPad Pro in sidecar over USB too. Streaming Spotify too.

 

[Nicole1980]

I do two things to insure the fans are always virtually silent:
First, I permanently disable Hyperthreading. As this lad explains - it doesn't hurt performance much, if at all.

And on long renders, where turbo boost is just going to drop after 15-30 seconds anyway (but still keep the system hotter) I'll disable turbo boost. On the iMacs, the base frequency is already pretty high so letting it run at the base freguency you still get damn good performance.

 

[Apple Knowledge Navigator]

The iMac pro NEVER ramped up the fans on

...

On the iMac 2020 the fan is WAY louder towards the end of a project or even if the room has no ac on

...

Do you have any idea on WHYthis is happing?

The iMac Pro features more and larger air intakes, 2 x larger fans, a large shroud that directs air from the intakes out to the exhaust, and a large exhaust port. It also features a massive copper heatsink, with shorter pipes between it and the GPU/CPU

The 'regular' iMac features smaller air intakes, just a single (smaller) fan, no shroud other than that which connects to the exhaust, and a smaller exhaust. The heat sink is smaller and the heat pipes travel longer to the GPU/CPU.

I'm not sure why people are so confused by all this as it's basic physics. The 5K iMac's thermal capacity is low in-so-much that you're willing to put up with fan noise.

compared to...

TL;DR - Apple cheaped out on the components.

 

[Andy5Kimac]

I don't have a 2020 5k iMac but I have the 2017 5k iMac. I had the i5 7600k version of it and the fans rarely came on. Only came on during long renders in Video editing. I upgraded to the i7 7700k and delidded my CPU with Thermal Grizzly Conductonaut (between the CPU die and IHS), it helped a lot with lowering my temps but my fans do come on way more often under heavy cpu usage then my previous i5 did. For normal usage though it's fine. The thing with the stock sensors in the iMac the fans don't come on til the temps hit 90+. Well this is what I noticed in my 2017. I use Mac fans control and have it set to start coming on around 50C and ramp up to full blast at 80C due to more heat provided from the i7. I also turn off my turbo boost during normal usage. Disengaging it helps lower the idle temps. 4.2ghz base clock is plenty for normal usage.

Anyhow I don't mind the loud fans. I rather have a cooler louder machine then a silent machine at CPU cooking temps...These 5K iMac's have 1 small fan cooling both the CPU and GPU so fan noise is expectable unless you look at the iMac Pro which has dual fans.

 

[johnscully]

As I'm thinking about buying an 2020 iMac: How is the fan noise in idle mode compared to the 21.5 inch model from 2019? Tried the 2017 model of the iMac 27-inch and sent it back because the fan was way louder in idle mode than my 21.5 inch (tried several units of the 27-inch as at first I thought there was a hardware fault). Where the 21.5 is practically silent from a normal distance at the desk (not totally, bit practically), the 27 inch was clearly audible all the time. Note: I'm just referring to the fan noise in idle mode(!), not under load with heavy tasks.

 

[Airch]

So when we speak about fan noise are we talking about from the pc itself or one built into the GC? If so, that’s AMD QC not as much apple……

 

[CheesePuff]

So when we speak about fan noise are we talking about from the pc itself or one built into the GC? If so, that’s AMD QC not as much apple……

there isn't a dedicated fan on the graphics card

 

[Airch]

there isn't a dedicated fan on the graphics card

Ah I see.

 

[vlaimir]

I have a problem solved every time by updating MacOS.

 

[pshufd]

I'm thinking of getting a refurbished one but they are expensive comparatively, since they didn't have SSD by default.

The 2020 iMac 27 has a 256 GB SSD in the base model.

There is a used one locally to me with i7, 32 GB RAM and 512 GB SSD for $950. It was listed 2 weeks ago and I'm waiting for it to drop to about $800. I see 2017, 2019, and 2020 iMac 27s coming on the market now.