(2019) 16" is HOT & NOISY with an external monitor! :(

[IceStormNG]

So in conclusion:
- If I want to use only one screen then Clamshell is enough
- If I want to use 2 screens, 1 of the macbook itself and an external monitor => should use SwitchResX

Urm yes and no. First one is 99% correct.
Second one doesn't matter. If you run more than one screen, GPU wattage will go above 18W no matter what you do.

And for the "heatsink". Yeah such a stand should be good enough. There are also some that have fans below the laptop to help cooling. Together with the thermal pad mod it will give you almost the "best" cooling you can get for this piece of trash.

Other possibilities are to reduce CPU clock frequency by disabling turbo boost. But that also reduced performance significantly as the CPU in the 16" heavily relies on Turbo Boost for proper performance.

 

[macdiablo]

Urm yes and no. First one is 99% correct.
Second one doesn't matter. If you run more than one screen, GPU wattage will go above 18W no matter what you do.

And for the "heatsink". Yeah such a stand should be good enough. There are also some that have fans below the laptop to help cooling. Together with the thermal pad mod it will give you almost the "best" cooling you can get for this piece of trash.

Other possibilities are to reduce CPU clock frequency by disabling turbo boost. But that also reduced performance significantly as the CPU in the 16" heavily relies on Turbo Boost for proper performance.

So what switchresx used for sir?

 

[saintmac]

So what switchresx used for sir?

Achieving low wattage with some screens.
For instance with the LG ultrafine 5k in clamshell I can stay as low as 5w for the GPU consumption without SwitchresX.
but to achieve that with an Apple Thunderbolt display, I need to use switchresX

 

[macdiablo]

Achieving low wattage with some screens.
For instance with the LG ultrafine 5k in clamshell I can stay as low as 5w for the GPU consumption without SwitchresX.
but to achieve that with an Apple Thunderbolt display, I need to use switchresX

Thank you, do you know the reason why some screens need to use it but some screems do not?

One more question: I heard that we should not let the lid closed when in clamshell mode because heat will damage the screen, is that true? is there a way to enable clamshell mode with the lid opened?

 

[Maconplasma]

Just curious, what is the final "experience" here? Are these fan issues a problem on the 5600m machines too, or just the systems with the other video cards?

I thought it was well understood by now that these fan noise/heat issues are due to the Intel processor which is why Apple has moved on. The GPU-type is only going to have a minimal difference.

 

[saintmac]

Thank you, do you know the reason why some screens need to use it but some screems do not?

One more question: I heard that we should not let the lid closed when in clamshell mode because heat will damage the screen, is that true? is there a way to enable clamshell mode with the lid opened?

I think it has to do with somethink like the GPU clock or memory clock being the same with both screens or not. I'm not 100% sure but the answer is for sure earlier in the thread ;-)

I'm not a native speaker but for me "clamshell mode" = "lid closed". I don't know a way around it.
I've heard that theory but I've done it for a while and don't see any damage.

 

[DubTEC]

I thought it was well understood by now that these fan noise/heat issues are due to the Intel processor which is why Apple has moved on. The GPU-type is only going to have a minimal difference.

I disagree. Last week I received a new MBP with 5600M GPU and the according memory (HBM2). Since a couple of days, I use it connected to a Lenovo T32-20P 4K display via USB-C with the internal display acting as a 2nd screen. So far, I didn‘t hear any fan noise whatsoever. Since I‘m sensitive to noise, I specifically went for this machine and configuration.

 

[make_mac_fast_again]

I run 4 external 1440p monitors and built-in display.

After applying VRM thermal mod it can run without any fans at all. Although the case bottom gets extremely hot.

Before thermal mod is was untenable due to throttling.

 

[juan985_Spain]

I hope Apple will launch soon the new Apple Silicon iterations for the 16". It is nonsense consumers have to tweak or apply mods to their laptop just to make it operate normally.

 

[richinaus]

I disagree. Last week I received a new MBP with 5600M GPU and the according memory (HBM2). Since a couple of days, I use it connected to a Lenovo T32-20P 4K display via USB-C with the internal display acting as a 2nd screen. So far, I didn‘t hear any fan noise whatsoever. Since I‘m sensitive to noise, I specifically went for this machine and configuration.

I disagree too.
I have the 5600M and had the lower spec GPU, and there is a big difference.

The CPU does still get hot and it is unusable on a lap. but the fans are vastly more quiet still.

 

[PeterJP]

I thought it was well understood by now that these fan noise/heat issues are due to the Intel processor which is why Apple has moved on. The GPU-type is only going to have a minimal difference.

No, not true. The problem is not Intel but AMD. When you have 2 screens connected, instead of trying to match the clock speeds required for each, AMD just turns up the clock to maximum. That also works if you want to serve each screen at the clock rate it expects, but it generates enormous amounts of heat. If AMD would manage the clock rate appropriately, this would not be necessary.

At least, that's how I understand it.

 

[IceStormNG]

No, not true. The problem is not Intel but AMD. When you have 2 screens connected, instead of trying to match the clock speeds required for each, AMD just turns up the clock to maximum. That also works if you want to serve each screen at the clock rate it expects, but it generates enormous amounts of heat. If AMD would manage the clock rate appropriately, this would not be necessary.

At least, that's how I understand it.

Yeah. That's the reason. And AMD does that on every GPU. Even the new 6000 Series Desktop cards do that. The reason why the 5600M has no problem with that is because it's low power and doesn't get that hot. GDDR6 is very power hungry.
AMD does that because otherwise, the displays would flicker or freeze. It was simply the cheapest solution to "fix" that issue.

Nvidia GPUs also do that to some extend if your monitors are not equal.

 

[FF89]

So in conclusion:
- If I want to use only one screen then Clamshell is enough
- If I want to use 2 screens, 1 of the macbook itself and an external monitor => should use SwitchResX

1 - correct, but
However, in my case only for specific resolution which are 720p, 1080p, and 4k monitor (All resolution tested in Dell U4320Q). When I tried 1440p monitor, failed (Dell U2520D QHD USB-C monitor). I need switchresx to create a custom resolution that reduce the refresh rate of the monitor a bit lower that 60 Hz (around 59.950 Hz in GTF simplied setting).

2 - Not yet achievable from my experience when including the macbook's internal display. only when both display are external monitors.
In my case, my Dell U4320Q 4K USB-C Monitor support picture-by-picture mode, it can be split into 2 separate monitor when connecting with two cables (4k resolution split into two displays with 1920x2160 resolution). And the results, no heating issue was found as long as my MBP in clamshell mode. (Side note: this is only for testing purpose. Not my usual way of using the monitor. I use the whole 4k resolution and resize my windows when multitasking).
Once I opened the lid (internal display):
- radeon high side will increase to 17-19 Watt (compared to 5-6 Watt in clamshell),
- Radeon memory proximity stay around 60 celcius (compared to 48-49 celcius in clamshell),
- Radeon GPU proximity stay around 56 Celcius (compared to 50-51 celcius in clamshell), and
- the fan starting to spin around 3400-4000 rpm (compared to 1700-1800 rpm in clamshell).
All reading takens during idle. If idle already like that, can't imagine when the MBP hogging more power with extensive tasks on top of the current burden.

Not to mention also the heat from thunderbolt proximity when you connect any peripherals to the thunderbolt 3 ports including the monitor, around 56 celcius (compared to 38 Celcius when not connecting anything). This is also another problem which contributes to the fan speed increase. It is like a self-defense mechanism of the mbp, "need to dissipate heat as soon as possible when too many sensors detect temperature above 55-60 Celcius". Just my thought.

 

[Minga089]

Has anyone noticed that their machine runs hotter and ramps up the fans more with Big Sur compared to Catalina? I resisted the upgrade a long time (until 11.4 actually) and i noticed it right away. While my machine seems now snappier overall it also runs about 5-10C hotter at idle and the fans are now noticeable at idle.

Catalina:

Monitors: External 24" 1440p monitor (2048x1152 HiDPI) + internal screen
Idle temperature: 55-60C
Fan speed: 1.800-2.200 rpm (silent)
Radeon High Side: 18W

Big Sur:

Monitors: External 24" 1440p monitor (2048x1152 HiDPI) + internal screen
Idle temperature: 60-65C
Fan speed: 2.200-2.600rpm (barely noticeable)
Radeon High Side: 18W

Maybe I should get it to the Apple Store and get the fans cleaned for the first time. Have been using my 16" for a year now.

 

[Maconplasma]

Has anyone noticed that their machine runs hotter and ramps up the fans more with Big Sur compared to Catalina? I resisted the upgrade a long time (until 11.4 actually) and i noticed it right away. While my machine seems now snappier overall it also runs about 5-10C hotter at idle and the fans are now noticeable at idle.

Catalina:

Monitors: External 24" 1440p monitor (2048x1152 HiDPI) + internal screen
Idle temperature: 55-60C
Fan speed: 1.800-2.200 rpm (silent)
Radeon High Side: 18W

Big Sur:

Monitors: External 24" 1440p monitor (2048x1152 HiDPI) + internal screen
Idle temperature: 60-65C
Fan speed: 2.200-2.600rpm (barely noticeable)
Radeon High Side: 18W

Maybe I should get it to the Apple Store and get the fans cleaned for the first time. Have been using my 16" for a year now.

Wow you must live in a very dusty environment. I’ve had my 16” MBP for well over a year and the fans don’t need cleaning. In fact I’ve been buying Apple laptops and keeping them for 5 years and never needed the fans cleaned. My iMac needed the fans cleaned after 4 years. Apple cleaned them because they had to perform a warranty repair on it but I don’t think they clean them as a paid service for a customer.

 

[Minga089]

Wow you must live in a very dusty environment. I’ve had my 16” MBP for well over a year and the fans don’t need cleaning. In fact I’ve been buying Apple laptops and keeping them for 5 years and never needed the fans cleaned. My iMac needed the fans cleaned after 4 years. Apple cleaned them because they had to perform a warranty repair on it but I don’t think they clean them as a paid service for a customer.

No, I'm not. In fact I don't know if I need cleaning or not. I had a 13" MBP mid 2014 before and I never cleaned the fans in 5 years and it was fine. It's just a possible explanation for the the suddently higher temperatures and fan speeds. Or is it really just the change from Catalina to Big Sur?

 

[Maconplasma]

No, I'm not. In fact I don't know if I need cleaning or not. I had a 13" MBP mid 2014 before and I never cleaned the fans in 5 years and it was fine. It's just a possible explanation for the the suddently higher temperatures and fan speeds. Or is it really just the change from Catalina to Big Sur?

On this respect it could be files on your system that are causing the sudden temperature change. I didn’t see any difference going from Catalina to Big Sur on my 16”MBP. If you haven’t done so as of yet I would recommend wiping your drive and reinstall your apps, one by one though rather than a dump just in case it’s a specific file that’s causing your issue.

 

[Minga089]

Thx, but I did a clean install and I am running Big Sur for weeks now (so no indexing etc.). I didn't experience any bugs or performance issues (my machine actually feels snappier), it's just that the the temps are slightly higher and the fans ramp up more.

 

[macdiablo]

Has anyone encountered damaged screen after a long time using clamshell mode? Any way to turn off the screen (but the lap is still working) while the lid opened?

 

[IceStormNG]

Has anyone encountered damaged screen after a long time using clamshell mode? Any way to turn off the screen (but the lap is still working) while the lid opened?

No and no.

Well, you can try to fool the hall sensor

 

[IceStormNG]

Thx, but I did a clean install and I am running Big Sur for weeks now (so no indexing etc.). I didn't experience any bugs or performance issues (my machine actually feels snappier), it's just that the the temps are slightly higher and the fans ramp up more.

That's mostly because of the more demanding UI on Big Sur. macOS UI gets more and more demanding with every release. So load increases.

Also: Big Sur has a bug that will cause high CPU load if you use a mouse with 500Hz or faster polling rate. You can see windowserver chewing through your CPU while moving the mouse. 250Hz and lower is "fine". It' still hilarious that the bug is still there. And still present in Monterey. I reported that issues multiple times. Apple really doesn't give a flying fu**.

 

[macdiablo]

If you want to use 2 monitors (the internal one also counts as a monitor) at the same time, you will run into the heating issue anyway. So you can only try to reduce the impact by dissipating more heat.

Clamshell mode only solves the issue if you only run one external monitor. In that case, SwitchResX is often not needed (at least not for the two monitors I tested and the one I use right now). I would try without that first. Look for the GPU wattage. if it's at around 18W, you might want to play around with it. If it's below 10W, then you're good.

Heatsink... do you mean padding the VRMs? Because that is definitely necessary if you don't want your Mac to become a jet engine. Other things that help are a cooling pad (with fans) or a vertical stand where the MBP is standing in with the fan exhaust pointing upwards. Both only really helps with thermal pad mod. Otherwise, the heat is trapped inside the MBP's chassis.

For the Cables... you might just want to try it out. BTW: The LG monitor you named has no Thunderbolt. It's just USB-C.

Stupid question: I'm using iStats, which one in this image is of GPU wattage?

 

[flowsy]

Stupid question: I'm using iStats, which one in this image is of GPU wattage?

"Radeon High Side"

 

[TheJulianJES]

No and no.

Well, you can try to fool the hall sensor

Afaik the 16" doesn't have a hall sensor (and magnet). It uses a sensor on the hinge mechanism to detect how far the display the opened.
(Most likely due to the slimmer bezels.)

 

[IceStormNG]

Afaik the 16" doesn't have a hall sensor (and magnet). It uses a sensor on the hinge mechanism to detect how far the display the opened.
(Most likely due to the slimmer bezels.)

Af.. damn.. totally forgot about that.