MacBook 16-inch Fan Noise

Some update from my side. I purchased a Samsung C34J791 34" bend ultra wide monitor I connected it to the Thunderbolt 3 port through my CallDigit and I see the following behaviour:

• MBP 16" open + external screen + turbo mode on, dGPU takes 18-19watt, temp between 65-70C fans around 3500 rpm with an hour conf calls through teams temp raises to 100C fans go to maximum
• MBP 16" clamshell + external screen + turbo mode on, dGPU takes 5-8watts, temp between 55-65C fans around 2300 rpm with an hour conf calls through teams temp raises to 70-75C fans go to 2500-2800 rpm
• MBP 16" clamshell + external monitor + turbo mode off, dGPU takes 5-8watts, temp between 45-50C fans 1700/1833 rpm with an hour conf calls through teams temp raises to 50-55C fans stay below 2000 rpm

I must say I am happy that I can work with turbo boost off (I do not need it for day-to day work) and in clamshell mode 12 hours straight without noise from the fans because they have to cool the dGPU.

As I said two days ago, I have the problem of noisy fans in my 16" MBP even when I am not using high-performance software. I have installed iStat and what I have read is quite impressive. The Radeon graphics card consumes over 17W, more than half of all MBP, while the eight core CPU consumes only 2.5W. All this only with the second HDMI monitor and also with two different adapters (Thunderbolt-HDMI). If I disconnect the second monitor, the consumption of Radeon drops to 0.12W. I am convinced that with two or more monitors the DGPU is always active, even if you try to turn it off by Sys Preferences or with other methods (Terminal). The problem seems to definitely reside in the discrete GPU Radeon. I haven't found any solution so far, if not using only one monitor at a time.

:-(

stefanosky wrote:

...

All this only with the second HDMI monitor and also with two different adapters (Thunderbolt-HDMI). If I disconnect the second monitor, the consumption of Radeon drops to 0.12W.

I have suggested many times on this thread:

Connect your displays with DisplayPort family, DisplayPort runs much cooler

I just got my 16 inch MacBook Pro and have the same issue.

This is my setup:

MacBook Pro (16 inch, 2019)

2,4 GHz 8-Core Intel Core i9

32 GB 2667 MHz DDR4

AMD Radeon Pro 5500M 4 GB

Intel UHD Graphics 630 1536 MB

with

Kensington TB3 Dock

with

LG 32 inch 4k display via Display Port

My tests results match what others where saying:

The MacBook 16 inch is staying cool when I use it only with internal monitor, or if I use my external 4k monitor with MacBook in Clamshell mode (display closed).

The graphics card is struggling, if I use both an external 4k monitor and the MacBook’s internal monitor and use high resolutions, e.g. 3360 x 1890 (HiDPI)

When I choose 3360 x 1890 in low DPI for the external display, the graphics card relaxes and the system cools down.

Even with HiDPI resolution the load of the system isn’t high and it’s only at around 65°C, but the fans still go crazy at around 4000 - 5000 rpm.

To summarize: The performance is very nice, but the fans go crazy when the graphics card needs to power an external 4k monitor together with the internal monitor.

I reported it to Apple and AMD.

An upgrade about my situation with the 16" MBP fans.

As I said a few days ago, I have a MBP 16 with a second low quality monitor, an HP 27o (1920x1080) connected with the MBP through an HDMI and a USB C / Thunderbolt adapter. With this configuration the fans very frequently start at high speed, even before logging in (if I leave the startup screen for more than a few minutes)! Once I entered the system I installed iStat with which I can read the temperatures in detail of many internal components. In normal conditions, since the discrete graphics card is always on due to the second monitor, the overall temperature never drops below 65 degrees, while with some active process (for example: a download) the temperature reaches 100 ° rather frequently. In this case the fans rise above 5,000 RPM. I then installed Turbo Boost Switcher, as someone had suggested in this post. This widget allows you to turn off the microprocessor boost. With the boost deactivated the overall temperature never rises above 63 ° and the fans are fairly quiet (2500/2600 RPM). If I disconnect the second monitor and work only with that of the MPB and deactivate the boost, the overall temperature drops below 50°, sometimes even below 45°.

At first I thought the problem was due exclusively to the graphics card always on, now I think it is a complex of things that cause the high internal temperature. Certainly the boost has an important responsibility, which is why I will continue to use Turbo Boost Switcher, at least until Apple has solved the problem.

I hope this can be useful for someone.

Note: in normal conditions the MBP does not show any difference with or without boost, regarding the performances.

I've done the exact same thing, use turbo boost switcher and it's worked the same for me as you've described.

Fans not gone above 2,500 and temp not about 65 connected to 2k Dell monitor with thunderbolt to DP cable.

When not connected to a monitor everything runs way cooler anyway, 35/40.

As you say, I'm also OK to use this work around for now in until there is an official software update from Apple to address the issue, fingers crossed.

I'm just glad I can now listen to music at my desk with headphones without it sounding like I've got a hoover running on the desk too!

Did you happen to read the thread? There are many people who have found how to fix this but some have been pretty good solutions for the issue that have opened the door for more control over the system. Some have found that changing the port in which the computer is charged helped. Others have found that Turboboost doesn't really help with speed but it does with temperature but turning it off. For some the CalDigit TS3+ dock works well (that's what I use because it's easy to connect and disconnect from the office). Some have increased their external monitor to 85+ hz and that drops it down quite a bit.

If you are having issues and you know your machine is defective you really need to contact Apple Support. Do not wait.

I don't think 10.15.5 makes any difference with 10.15.4. The 5500M dGPU still consumes 5w with built-in screen and 18w using external 4K monitor on my computer. And, I don't think Apple will fix this problem anymore. I have called the customer service twice and submitted to engineers for review. They all gave me same answer saying "this is completely normal and designed as this way".

If you do think about using external monitor with built-in screen and cares very much about noises, try to grab i7+5300M version. It's quite cooler than i9+5500M. And rumors said UltraFine series monitors and high refresh rate monitors have better thermal performance too.

I have found one solution to this.

I had been having the same problem for several days now. The fans were spinning to the max 100% of the time. At the time I was running Chrome and I had around 20 tabs open.

I decided to turn off the "Use hardware acceleration when available" setting that is enabled by default. As soon as I did that, not a minute went by that I literally started hearing the fans spin down all the way to where they are barely audible.

Thus, it seems obvious the culprit here was the constant use of the graphics card.

From reading other comments here related to the number of screens, I want to point out that I am also running two external monitors, one at 4K and another at UHD. Three of the four connections are taken. So I can say (at least in my case), that had nothing to do with it.

Hope this helped!

Not sure if anyone else has mentioned it, but Turbo Boost Switcher has helped me. Free version is great but I bought pro so it enables turbo boost for certain apps (e.g. video rendering). Seems OSX likes to do every calculation at max possible speed, even when it's totally unnecessary, so being able to say "woah there maccy boy, take a breath..." is quite useful.

I found a workaround for my setup.

The MacBook stays cool and silent at 60-65°C with 2.000 to 3.000 rpm when I connect the original charger to the right side USB-C port and the TB3 dock with 4k monitor to the left side USB-C port and also disable Turbo Boost.

That’s not the ideal setup as I’d like to have Turbo Boost enabled and only connect the dock with a single cable, but at least it’s working now with no audible fans and moderate temperatures.

Some people here is discussing if the dGPU using 18 watts or more is a bug or not, for me that's not the issue here, the issue is that the machine gets really hot and the fans go full speed just by connecting an external monitor.

In my case what make me think this is a bug is that if I change the refresh rate to 144 hertz the machine is almost perfect (most of the time), the fans only get above 2500 RPM when running some specific apps (and that's perfectly normal) but if I change the refresh rate back to 60 hertz, the fans will go crazy just by browsing the web in safari or reading an email (the fans can go all the way up to 4500 RPM, almost full speed!!). So that's definitely not normal at all. And on top of that on 10.15.5 the fans will run faster that they do in 10.15.4 when doing the same stuff (like reading an email or browsing the web), so again that's not normal at all.

Right now I'm using 10.15.4 with a refresh rate of 144 hertz that makes the machine works with almost no issues (almost).

Hola Pedro, do you have an external display attached? If so, could you try to disconnect that external display and see if the fans go down.

For heavy duty graphic tasks the Radeon GPU can help, but with external displays the CPU appears to work hard, which causes its temperature to rise so the fans need to cool it.

There are 3rd party apps that disable the turbo boost feature, so the fans will become quiet. but of course then the performance for heavy duty tasks will drop significantly.

We'd like to hear your findings.

Kind regards,

Peter

PhotogWithMac wrote:

Edit: okay I looked it up. The “discrete” GPU is the powerful extra GPU and the “integrated” is the low power standard GPU. So you somehow activated the discrete GPU without external displays connected. How did you do that?

Right. The "discrete" GPU is, in my case, the Radeon Pro 560X. The "integrated" one is the Intel UHD Graphics 630.

Certain scenarios will force the system to "turn on" (start using) the discrete GPU:

1. Use certain applications that request it (OBS is one such app).
2. Attach an external monitor.
3. Disable "Automatic graphics switching" in the Energy Saver pane in the System Preferences.

When I mentioned in my writeup that I tested a Handbrake encode with the discrete GPU enabled, I had used option #3 above to force the system to use the Radeon GPU.

PhotogWithMac wrote:

i now understand that handbrake had less power available because the discrete GPU was consuming power as well.

That is the wrong conclusion to draw from this. "Handbrake" doesn't consume power, it consumes CPU cycles. What it likely means (corroborated only through anecdotal "because I watched the CPU Frequency graph during the process" evidence) is that the CPU itself was throttled simply because the Radeon GPU was active. It wasn't doing any processing while Handbrake ran [as I recall], but the CPU still ended up running slower.

I chalk that up to the GPU adding heat to the system and the CPU clocking itself down to compensate.