MacBook 16-inch Fan Noise

Reseting the SMC with and without the charger plus disabling (not removing) Abode Cloud, Box, Drop box, removing Norton, Not opening Mail app without wifi. All these vodoo tricks helped remove any high temp high fan speed behavior.

I don’t get high speed fan very high temp when the laptop is plugged to a monitor. However the temp rises from 30 celcius in idle to 51. I haven’t tried to leave the laptop plugged to an external screen for more than 30 min.

hatemal wrote:

I use iStat menu.

Thank you for that!

I just installed that and replicated your scenario (except I just had one external monitor running at 1080p connected because why not?)

I found that my GPU (Radoen Highside) was using 18.8w compared to yours being just under 9 when connected to the external monitor, so likely that's where the heat is coming from.

This reaffirms the theory it's the GPU causing the heating problems, will take it up with Apple support now.

I did some investigation and discovered the abnormal power draw of the 5500m ONLY occurs when there are two displays running at once, this includes the MacBook display.

So if I shut the lid on the MacBook and connect to one external display even at UHD it only draws less than 5W, the moment I connect a second external display or open up my MacBook lid it jumps to 20W.

I thought this might be a red herring, as in the macBook uses only intgrated graphics when only one display is connected so as an experiment I ran four 4k HDR videos on the screen, sure enough the power draw of Radeon highside went up as expected and caused the fans to speed up indicating that the MacBook was using the Radeon graphics.

So if any Apple engineers are reading this, my semi grounded theory is that the Radeon 5500m is buggy and its power usage disproportionately spikes up when powering more than one display.

Please look into it or hire me to look into it! I'm not a systems programmer but willing to learn :D

After following this post for almost a month, I did my best to do my own research about that issue.

I own the base model and also have these issues.

I can confirm that I have the same issue. While I'm using an external monitor and the MBP 16 screen, the watt usage of the GPU rising to almost 20 watts, what leads the MacBook pro to overheat (Which directly makes fans work more intensively). The temperatures in the idle state are around 60-celsius degrees.

BUT, while I'm connecting the MacBook pro to 2 monitors, and use the MacBook Pro in clamshell mode, the watt usage of the GPU is in the right range, and the temperatures too.

I know it does not satisfy any of us, but for now, I highly recommend everyone to use the laptop in clamshell mode with external monitor or even with 2 if needed. At least until the problem is resolved.

All we have left to do at this moment is to report the problem to the support/send feedback and hope the company will behave fairly towards those who have invested the most money for this product.

Here is what I'm getting with dual 4k screens connected:

It's in clamshell mode. No fans are running. Affinity Publisher, Adobe Indesign, Adobe Photoshop are all open along with mail, settings, and teamviewer.

I just loaded FCPx with a full timeline and the fans kicked up for a little bit. The fans don't go fast unless they are actually under a heavy load of opening really big files in Affinity or using FCPx . After processing a little bit they went back down to nothing.

If I actively use FCPx it will certainly push up the fans but that's only because it's rendering effects. Once it's done they go back down. It runs so well though that it has no problem cooling and so you don't have the throttling we had in the 15" versions.

Having 2 or 3 screens active seems to make no difference here.

If you have cleared the caches (I'm told that doesn't matter but I believe it does), reset PRAM, reset SMC, I would say something is wrong.

Are you using the MacBook Pro in clamshell mode? If yes, try to run it while your lid is open, and then check the temperatures and your GPU watt usage, and then I guess that you'll find out that those aren't in the right range.

I also have this issue, only seems to show up when an external monitor is connected through usb c. My cpu and gpu went to almost 100 degrees celcius and suddenly rebooted. It happens multiple times a day. When I remove the external monitor the temp drops to around 40 degrees celcius for both cpu and gpu

I wrote about it yesterday, while using external monitor/s in clamshell mode there is no problem.

The issue begins while you are using the internal display as well, i.e. with the lid open.

That's the case:

The lid is open -> the watt usage of the GPU is rising to 18-20 watt -> the temperatures are rising to 60-celsius degrees in idle state -> doing basic tasks -> the fans start to work hard.

We can say whether it is observed or not if and only if we see the real wattage of the GPU. I have the same configuration and use the same dock and tested my configuration with 3 different displays: HD, 2k and 4k, any combination of two of them + closed lid = 5w, opening the lid = 20w.

@brycesteiner It would be great if you could install iStat Menu at least to check the power consumption, it has 14 days trial.

I just noticed that when I changed my external monitor resolution to 1080p from normal 2560x1440 Radeon is powered only by 3.5 Watts. Temperatures are falling down to normal levels (like when working without external monitor.)

Can anyone confirm that it is working on his mac?

When I select any other, higher resolution it goes to 16.5 - 17 Watts.

One thing that keeps that Discrete GPU HOT is using a "legacy" display interface, such as HDMI. "Legacy" display interfaces feature the old CRT "heartbeat" refresh. They resend each and every pixel on the screen every refresh period, and the data rate at high resolutions means a LOT of pixels are re-sent 60 times a second. Sending all that data 60 times a second generates heat, and for nothing.

If your display has a DisplayPort family interface, there is a screen buffer in the display. Once the screen stabilizes, only the changes are sent. When the display stops changing, the link goes nearly quiet, and far less data sent can mean far less heat generated.

So I would expect that reducing resolution when using a "legacy" interface would reduce heat, possibly in a measurable way, and reducing resolution when using DisplayPort family would make no discernible difference (because you are already 'doing the right thing' by using DisplayPort family).

Do you use your machine with an external display and opened lid ? In this configuration it will be extra ~20°C what can make thermald daemon crazy, as it has quite low thresholds. I don't believe there is an MBP 16 that works without extra heat in this configuration.

I use mine in clamshell mode and it never goes below 60 but it can get to 90+ just by browsing the web. As soon as I disconnect the external monitor the machine goes back to 50/48 and after a minute the fans go back to 1900 RPM. Check attached screenshots (the first 2 screenshots at 95 and 62 are with the external monitor connected in clamshell mode and the other 2 at 50 and 48 are without an external monitor connected)

Summary of the Situation: 

1- Fan Noise and Heat issues at MacBook Pro 16 Inches. 

2- All Models are affected. 

3- It looks like all MBP 16 are defected. 

4- The issue appears connecting external device to the USB-C. In special external display.

5- Issue is affecting by all kind of display 4K, Full HD.

5- Several test shown it is a hardware issue. (Test running with windows software shows same results).(Latest software updates have not improved the situation). Other users could consider a software issue.

6- The best action is to report to Apple. https://www.apple.com/feedback/

7- Till now Apple has not reported any issue.

8- It is a worldwide issue and not an special Lot of computers. From Poland to USA, Germany and Italy.... worldwide is reporting the same failure at fan noise and overheating at just browsing.

9- Some test shown the issue is in relation with the GPU. 

10- Apple support can not inform if the issue is resolved. 

11- It is recommended to return the MBP within the 15 days period of guarantee. 

12- All the users that have contacted and followed the indications of Apple support, for example : restart in safety mode and so on.. have not observed any improvement.

13-Bunch of people is waiting for a solution or communication from Apple in order to buy a new MBP. (Three months gone).. 

14- Several people reported that computer work almost properly with no external connections. 

15- Fan loud Issue improve if you close the lid. 

16- Some people reporting better behaviour if you connect MBP to a dock.  Some people reporting that there is not improvement even with connection to a Dock. 

17- Some people reporting the fans goes crazy just connecting external hard drive. This was my case connecting hard drive through a hub to the USB- C. Please confirm if still the case. 

18- Media reports: 

https://m.youtube.com/watch?feature=youtu.be&v=EkmdHVfk4XE

https://forums.macrumors.com/threads/16-is-hot-noisy-with-an-external-monitor.2211747/page-23

https://www.spidersweb.pl/2020/02/laptop-jako-desktop-poradnik.html

https://www.spidersweb.pl/2020/02/macbook-pro-16-przegrzewa-sie-problem.htm

19- If I missed something, just added to the summary. Thank you

My question, what else can we do?.

This is really frustrating.

Hi,

I have also problem with too hot 16-inch MacBook used with external monitor connected through Belkin Thunderbolt 3 Express Dock HD.

My previous MBP 15 2017 had 43*C degrees when idling.

My new MBP have about 53*C degrees when idling and it is realy annoying. During web browsing temperature fastly reaches to about 60*C degrees.

BUT when I switched default monitor resolution to scaled resoluton (1920x1200 -> 1920x1080) my MBP 16 idling temperature drops to about 44-45*C degrees.

All given tempeatures was in clamshell mode.

Strange.

Jan