MacBook 16-inch Fan Noise

RESOLVED: For those of you using a second monitor.

My 16 was plugged into the Usb c HDMI cable, AND plugged into the Macbook charging cable, thus "double charging" my laptop which would cause the fans to ramp up and my computer would over heat. As soon as I removed the Macbook charger the fans returned to normal. I didn't realize the newer Usb C HDMI cables would also charge the device from my computer monitor.

Hope this helps!

Close dropbox, box, adobe Cloud,... any Aps that synchronizes in the background

Reset the SMC here is the procedure (I was holding for 20 seconds not 7 as they suggest):

1. Shut down your Mac.
2. On your built-in keyboard, press and hold all of the following keys. Your Mac might turn on.

• • Control  on the left side of your keyboard
  • Option (Alt)  on the left side of your keyboard
  • Shift  on the right side of your keyboard

Keep holding all three keys for 7 seconds, then press and hold the power button as well. If your Mac is on, it will turn off as you hold the keys.

Keep holding all four keys for another 7 seconds, then release them.

Wait a few seconds, then press the power button to turn on your Mac.

If you do this and don't notice any significant improvement then get your laptop replaced

as you see on my previous post apps are behaving weirdly on Catalina using unnecessary CPU power, especially Mail, probably Safari as well.

Hope this helps.

So I have made some further testing:

• With another external display (HP Z32) connected through usb-c cable with laptop lid opened: 20W radeon power consumption, fans ~3000 RPM, 65-70C CPU and GPU temp, fans audible
• With HP Z32 connected AND laptop lid closed: 5-8W radeon power consumption, fans ~1800 RPM, 50-55C CPU and GPU temp, fans inaudible - BUT sometimes I have to disconnect the usb-c cable and reconnect again, because Radeon gets stuck at 20W and would not drop to 5W
• With no external display connected: Radeon 0-3W, fans ~1800 RPM, 45-50C CPU and GPU temp, fans inaudible...

All tests were made during regular work (web browsing, coding) with ~10% CPU usage.

I was not able to get to less than 20W before on a different usb-c 4K display with lid closed so I am wondering if this was fixed by recent update to 10.15.3 or it depends on a display. Will test more when I get back to my other LG 4K display where Radeon was constantly drawing 20W even with lid closed.

The downside of using laptop in clamshell mode is that I cannot use fingerprint reader to unlock password manager etc - so back to good old password typing like on my previous 2013 15" MBP... At least I don't constantly smell the burning metal from heatsinks being cooked at 70-90C for whole working day...

TailsDog wrote:

Why would it produce extra heat, more than before doing normal things?

6 years ago I could plug a macbook pro in to an external monitor, watch some video and do some normal tasks and there was no issues

Extra Heat:

These are not the same processor used before. These utilize a separate massively fast-and-hot Memory/IO-controller part that is required to decode memory addresses larger than 16GB, the previous MacBook Pro limit. This heat is generated at all times, even when idle. And More RAM memory than ever before generates more heat as well, even when idle.

The other issue is that Apple Engineers have boldly removed Thermal Throttling. Any background task that worked too hard doing un-needed things (like anti-Virus scanners or DropBox file syncing USED to get throttled by having its priority lowered. Without throttling, that does not happen any more, so "ordinary" background things that used to be "no worries" now are free to go crazy, and crank up the fans. These sorts of processes are slightly throttled by their need to do I/O, but the SSD drives are faster than ever as well.

suggested experiments: run a plain vanilla MacOS image with no third-party add-ons, or run in Safe Mode, so that only Apple processes (and few of them)are launched automatically. ¿Fans still too loud?

6 years ago external displays:

At that time it was impossible to run a display as large as the 4K displays we now take for granted. Each doubling of the screen size quadruples the number of pixels required. If you are also using "32-bit color", the number of bits for each pixel pixels grows from 8-8-8 to 10-10-1, a six bits per pixel increase times the number of pixels on the screen.

If you use "legacy" interfaces like HDMI, the entire screen is refreshed every 60th or 30th second, generating still more heat, because it all has to be fetched and rasterized again for each interval.

suggested experiments: set the resolution of your external display to HD 1920 by 1080, and be certain that you are using only 24-bit color and DisplayPort family connections. ¿Fans still too loud?

I just want to summarize so far what I am seeing:

Symptoms:

When using an external monitor and no major processes causing load

• Big power increase for dGPU - runs around 20w
• Big temperature increase 30c+, fans spin up, area above touch bar very hot to touch
• Occasional temperature spikes to 90c+ for no apparent reason (activity monitor shows no high load processes)
• Activity monitor sometimes shows very high GPU time for WindowServer
• iStat shows dGPU memory filling up, sometimes 10 minutes after power up also shows spikes to 100% for dGPU processor
• When running processes that do push the system GPU and CPU things can be unstable, graphical glitches and sometimes crashes.
• Touchbar can hang when very hot
• dGPU causes blue effect on dark or light lines when True Tone or Night Shift is active (this maybe unrelated but it does not happen with the integrated graphics)
• Reports that using windows on bootcamp also causing high temps

What I've tried:

• Deactivating background processes, syncing, indexing etc
• Safe mode
• Different cables
• Turbo Boost Switcher
• Less apps running, less browser tabs not playing video
• Different resolutions
• Frequent reboots

What seems to work:

• Not using an external monitor
• Using an iPad with sidecar for an extra display
• Using an eGPU
• Clamshell mode, lid shut connected to keyboard and monitor(s)

As I am now using my MBP16 connected to a 4k monitor daily working from home, I've found Turbo Boost Switcher Pro is essential to keep things tolerable.

When connected to the monitor, I turn turbo boost off. It's enough to keep fan speeds at ~2800 RPM while just using office apps, and ~3200 RPM while running conferencing apps (Zoom, Webex, Teams etc). The fans are audible at both speeds, but tolerable.

If I don't turn turbo boost off, conferencing apps send the fans speeds into the 4000s and beyond, which is completely unworkable for video conferencing. It only takes brief background activity to cause the CPU to spike in frequency, which sends the thermals (and fan speeds) up, which takes ages to recover from. Preventing turbo boost prevents a spike in thermals when background activities run.

It's a stupid workaround, but it's just enough to keep the badly compromised thermal budget in check. I couldn't use the machine all day, every day without it. And I am soon reminded if I have forgotten to turn off turbo boost - the fans are shouting at me within 15 minutes.

I am fortunate that my job only requires office apps and video conferencing. It's not ideal, but the setup works. It would be much more difficult if I was a coder or was working with media.

In my spare time, I use my MPB for photography, but I always do that without an external monitor - everything works fine then.

One fix suggested many times on this thread is to use a third-party Utility to disable the processor TurboBoost feature.

Turbo Boost allows, when lightly loaded, one processor to run 'stupidly fast' and only slow down when it is so HOT it will start to cause damage. It is total specsmanship, and not of any real discernible value except when doing completely single-threaded operations like compiling (in which case it can be momentarily re-enabled).

This computer was built with a ninth generation 14nm processor. The only way to meet the target performance was to make it a six or eight core processor. This processor generates an enormous burst of heat when it does Turbo Boost, and there is only one cooling rail shared by both the CPU and GPU. So getting Either side too hot ramps up the fans.

This processor was supposed to be an eleventh-generation 7nm processor, but intel is three years late, and is only starting to ship its tenth generation 10nm processors now.

Apple DID redesign the cooling system for this specific Mac. A new, high-efficiency fan is used. But for some uses, that still does not make the system quiet enough.

Some of the best advice is to install Turbo Boost Switcher and turn off CPU Turbo Boost. This reduces the huge sudden overheating brought on by Turbo Boost, that simply does not translate into real-world performance gains.

This computer was built with a ninth generation 14nm processor. The only way to meet the target performance was to make it a six or eight core processor. This processor generates an enormous burst of heat when it does Turbo Boost, and there is only one cooling rail shared by both the CPU and GPU. So getting Either side too hot ramps up the fans.

This processor was supposed to be an eleventh-generation 7nm processor, but intel is three years late, and is only starting to ship its tenth generation 10nm processors now.

Apple DID redesign the cooling system for this specific Mac. New, high-efficiency fans are used. But for some uses, that is still not enough.

Some of the best advice is to install Turbo Boost Switcher and turn off CPU Turbo Boost. This reduces the huge sudden overheating brought on by Turbo Boost, that simply does not translate into real-world performance gains.

Changing away from HDMI to DisplayPort family (or to ThunderBolt-display or USB-C display) will reduce the Voltages and slightly reduce the heat generated. It is a good thing to do, but it may not be enough to solve this issue by itself.

This computer was built with a ninth generation 14nm Intel processor. The only way to meet the target performance was to make it a six or eight core processor. This processor generates an enormous burst of heat when it does Turbo Boost, and there is only one cooling rail shared by both the CPU and GPU. So getting Either side too hot ramps up the fans.

This processor was supposed to be an eleventh-generation 7nm processor, but intel is three years late, and is only starting to ship its tenth generation 10nm processors now.

Apple DID redesign the cooling system for this specific Mac. New, high-efficiency fans are used. But for some uses, that is still not enough.

Some of the best advice is to install Turbo Boost Switcher and turn off CPU Turbo Boost. This reduces the huge sudden overheating brought on by Turbo Boost, that simply does not translate into real-world performance gains.

For external displays, changing away from HDMI to DisplayPort family (or to DisplayPort over ThunderBolt or USB-C) will reduce the Voltages and slightly reduce the heat generated. It is a good thing to do, but it may not be enough to solve this issue by itself.

How to fix your 16-in MacBook Pro (Don’t return it!)

https://www.youtube.com/watch?v=EkmdHVfk4XE

Hey everyone,

I have a solution that has worked for me. My big issue was I use an external monitor and I produce music so I can't have my fans loud while I am using guitar. Just like you guys I faced the fan issue---even with temps in the 60-65 degree celsius range my fans were on blast with an external monitor. I did 2 things this evening that seem to have COMPLETELY resolved the issue (not sure which did it or if it was both together)

1) Click on your battery/charging icon in the menu in the top right of your screen -> Click "Battery Preferences" -> Power Adapter -> Automatic Graphic Switching (uncheck)

2) Go to System Preferences by clicking the apple icon on the top left of your screen (make sure to select this icon on your laptop monitor, not your external monitor). System Preferences -> Display -> Uncheck True Tone

I went from having my fans running full blast in my music software and even browsing the internet to now having them be inaudible. It was so bad for me that I considered selling the machine, but after discovering this resolution this evening I'm taking my listing down. Honestly I notice no difference without the true tone. If anything my external monitor looks a little better.

Hope this was helpful!

16-in MacBook Pro heat and performance:

This computer was built with a ninth generation 14nm Intel processor. The only way to meet the target performance was to make it a six or eight core processor. This processor generates an enormous burst of heat when it does Turbo Boost, and there is only one cooling rail shared by both the CPU and GPU. So getting Either side too hot ramps up the fans.

This processor was supposed to be an eleventh-generation 7nm processor, but intel is three years late, and is only starting to ship its tenth generation 10nm processors now.

The drive in this computer is more than 100 times the typical speed of computers a decade older. It is the "Muscle Car" of notebook computers. If you have installed software that wastes computer resources on a regular basis, such as speeder-uppers, Cleaners, Optimizers, Virus Scanners, third-party file Sync-ers such as DropBox, OneDrive, or GoogleDrive, or a VPN, it will do busywork at previously-impossible speeds — heating up at a ferocious rate.

Apple DID redesign the cooling system for this specific Mac. New, high-efficiency fans are used. But for some uses, that is still not enough.

Some of the best advice is to install Turbo Boost Switcher and turn off CPU Turbo Boost. This reduces the huge sudden overheating brought on by Turbo Boost, that simply does not translate into real-world performance gains.

For external displays, changing away from HDMI to DisplayPort family (or to DisplayPort over ThunderBolt or USB-C) will reduce the Voltages and slightly reduce the heat generated. It is a good thing to do, but it may not be enough to solve this issue by itself.

Solution, then backstory... Turbo Boost Switcher Pro - how $9.95 saved my MacBook Pro!

I purchased the 16in 2.4GHz i9, 2TB/32GB/8GB on 12/31. As a music producer, the fan noise was simply unbearable. After 6.5hrs at the Apple Store yesterday (2 hrs troubleshooting, then 4.5hrs migrating to a replacement). I came home with a new one on the chance I had one with bad thermal paste or something. I had almost thrown in the towel because it takes 18+ hours to install all my software, but thanks to Migration Assistant it only took 4 at the store. I was coming from a Late-2014 iMac 5k (the best computer I've ever owned). I said, I would gladly trade performance for a quiet computer... well, I found it with Turbo Boost Switcher Pro. I still have the power when I need/want it, but most of the time, I want silent fans and longer battery life. Now I have it!

[edited because I accidentally hit post prematurely]

Having the same problem.  And what seems to have helped a lot is unchecking 'Automatic Graphic Switching' in the Energy Saver pan in System Preferences.

Have a 2.4 GHz, 32 GB, Radeon 8 GB, 2 TB.  It's connected to two external Dell monitors through HDMI adapters.  Just running a youtube video in Safari would send the fans spinning up to 4500 or more.  Playing a song in Logic took it up to 5500 and more.  Distractingly noisy.

If I unplugged the two monitors, while the video was running, the fans immediately started to slow down and things became quieter.  So something to do with external monitors I suppose. Talked to support and they recommended, initially, to reset the SMC.  This did not help.

But then I unchecked the Automatic Graphics Switching (with the monitors plugged in) and the fans immediately started slowing down.  They are now running about 2800 and are pretty quiet with the youtube video playing. I did start a Logic session and playing and the fans started getting noisy again, but perhaps that's a bit more expected.

Still some tests to do, and it's not ideal, but I'd be interested to know if this helps anybody else.