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I just recently got the MBP 16 and have this as well. But knowing Radeon and Nvidia cards from windows I say this is normal and both Radeon and Nvidia team already knows about this for so long.
On Windows if you run 2 monitors at 1080p and 1 monitor is 59Hz and the other is 60Hz the GPU Ram freq. will bump up to max thus causing more power draw. Same thing will happen if you run 2 monitors with both 60hz but with different resolutions. But if you run 2 monitors with identical resolutions and refresh rate it goes back to power save mode on idle and thus drawing less power.
So using 2 identical monitors at a time or just using 1 monitor and closing the laptop is ideal.


Hi @Hibi Runrun,

Thanks for your reply.

In the previous posts, you'll see replies from other MBP users e.g. conversations on this page, that they don't have this extra power draw (and hence the heating and fan-noise probelm) with older MacBooks such as MBP-2017.

> But knowing Radeon and Nvidia cards from windows I say this is normal and both Radeon and Nvidia team already knows about this for so long.

There were speculations that this might be something specific to the new AMD 5300 and 5500 chips. Do you know the exact models of the Radeon and Nvidia cards you referred to above?

Thank you.
 
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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 temperatures was in clamshell mode.
 

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Well the new cable helped me with the clamshell mode, power draw dropped from 19-20W to 5-6W ;)
I don't know your exact setup, but other things changed as well, I run at 19w in clamshell no matter what cable I use..
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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 temperatures was in clamshell mode.
I never go below 60 at idle, do you have istat and could check the radeon high side watt usage in those scenarios?
 
Had an important 15 inch fail on us yesterday and needed an immediate replacement. Picked up a stock 2.3/16/1TB/5500 from the Apple Store and set it up yesterday, away from the office. Erased and reloaded 10.15.3 from scratch, manually re-installed all apps and data, no migration or time machine restore. Great screen, acceptably little coil whine, no panics, manufacture date 10-28-19.

This morning, brought it to the office as indexing had finished and nothing was hogging CPU. Plugged it in at my desk to the LG 4k 24 inch monitor that Apple sells and expected the worst...

It's been 3 hours and NO loud fans! Laptop screen is open and iStat says 18w on the GPU and ~1600 ->~1800 on the fans. Apps running: Kiwi for Gmail, safari, chrome, photos, Tweetbot, messages, bbedit, Authy, slack, Trello, activity monitor, cyber duck, preview, adobe acrobat. Fired up photoshop and opened a few hundred mb file. Still NO noticeable or loud fan spinning.

I'm happy to look at any settings to try and help!
 
Loud fans isn’t this issue. Loud fans is a symptom of the issue being that the GPU is using full wattage just by being plugged into an external display (20w).
I too don’t get loud fans when my anbient temp is in an air conditioned office at 23° c. However in a non air conditioned room with slight humidity and 26° c my fans do spin up with connected to an external display. When I’m not connected to the external and in the warmer environment the fans do not spin up. Because the dGPU is only using 5w ~.
 
## Results under Catalina 10.15.4 Beta 2

I upgraded my MBP-2019 to Catalina 10.15.4 Beta 2 (19E234g) today, and noticed the following changes:
  • "Radeon High Side" is almost always at ~3.0 Wwith or without charging cable attached (screenshot-1 below).
    • If you have a look at my post here, you'll notice that under Catalina 10.15.3 Final, "Radeon High Side" ramains at ~0.10 W most of the time.
  • "Radeon High Side" still reached ~19.5 Wwhen an external 4K monitor is attached (screenshot-2 below).
    • More details on the Dell P2415Q screen, resolution, refresh-rate etc. are here.
Thank you.

## Screenshot 1 (without external monitor)

Radeon High Side without Dell P2415Q- Catalina 10.15.4 Beta 2.png


## Screenshot 2
(with external monitor)

Radeon High Side with Dell P2415Q- Catalina 10.15.4 Beta 2.png
 
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Just got the base 16. And the ~19W dGPU power consumption when using external monitor AND laptop's monitor is the only issue I have with the laptop. You'd think that a 7nm dGPU would be more power efficient...

I'm using some generic usb-c - hdmi/usb 3.0/sd card reader hub and a 1080p (!) monitor. If I close the laptop's lid, the power consumption drops to 5w, otherwise around 18-19W for just the Radeon. Of course, it will heat up eventually and will push the fans. Not liking this fan noise and heat when idling just because I attached a 1080p monitor.

Beta 2 didn't help with the issue.

@gsbabil: I upgraded to beta 2, too. Radeon Highside shows 0.1W when not using external monitor. I don't have the "always 3.0W" thing.
 
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Just got the base 16. And the ~19W dGPU power consumption when using external monitor AND laptop's monitor is the only issue I have with the laptop. You'd think that a 7nm dGPU would be more power efficient...

I'm using some generic usb-c - hdmi/usb 3.0/sd card reader hub and a 1080p (!) monitor. If I close the laptop's lid, the power consumption drops to 5w, otherwise around 18-19W for just the Radeon. Of course, it will heat up eventually and will push the fans. Not liking this fan noise and heat when idling just because I attached a 1080p monitor.

Beta 2 didn't help with the issue.

@gsbabil: I upgraded to beta 2, too. Radeon Highside shows 0.1W when not using external monitor. I don't have the "always 3.0W" thing.


Hi @buran-energia,

I upgraded to beta 2, too. Radeon Highside shows 0.1W when not using external monitor. I don't have the "always 3.0W" thing.

Thank you for reporting this. I'll keep an eye on mine and report back if I see a change.

In order to crosscheck the ~3.0 W "Radeon High Side" behavior under Catalina 10.15.4 Beta 2 (19E234g), I restarted my machine a few times now for a clean start and noticed something new -- if you restart the laptop under Catalina 10.15.4 Beta 2 (19E234g), does your screen flickr/blink 2-3 times with the apple logo immediately before the log-in window is displayed? Is this normal?

Please let us know when you can. Thanks a lot again.
 
It's been 3 hours and NO loud fans! Laptop screen is open and iStat says 18w on the GPU and ~1600 ->~1800 on the fans. Apps running: Kiwi for Gmail, safari, chrome, photos, Tweetbot, messages, bbedit, Authy, slack, Trello, activity monitor, cyber duck, preview, adobe acrobat. Fired up photoshop and opened a few hundred mb file. Still NO noticeable or loud fan spinning.

I'm happy to look at any settings to try and help!
All those programs are low impact programs, sure they take up some ram, but the stress on CPU is minimal.
Depending on your room temp etc, your fans might not be super loud, I'm running at a steady 2k rpm with 60 degree at idle, and don't notice the fans that much in an office environment..
But if I start a virtualbox machine, compile a program, download/sync with gigabit speed or any other heavy cpu load, my temp goes up to 80-100 degrees and fans will ramp up to 5k+ over time.

The system will handle 30w of load of course (your scenario with 20w gpu and 4-7w cpu). But when you start loading the CPU, because the GPU is already pinned at max, the overhead is much smaller. You can consider it the same as running a full blown AAA game title constantly with full GPU and CPU load.

So the issue for me, is that I can't do regular tasks I did previously, on a system that should handle it with ease. If I run without external screens, I hardly ever hear the laptop even under heavy CPU loads as I have 15-20watts of extra headroom on the cooling system.
 
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Had an important 15 inch fail on us yesterday and needed an immediate replacement. Picked up a stock 2.3/16/1TB/5500 from the Apple Store and set it up yesterday, away from the office. Erased and reloaded 10.15.3 from scratch, manually re-installed all apps and data, no migration or time machine restore. Great screen, acceptably little coil whine, no panics, manufacture date 10-28-19.

This morning, brought it to the office as indexing had finished and nothing was hogging CPU. Plugged it in at my desk to the LG 4k 24 inch monitor that Apple sells and expected the worst...

It's been 3 hours and NO loud fans! Laptop screen is open and iStat says 18w on the GPU and ~1600 ->~1800 on the fans. Apps running: Kiwi for Gmail, safari, chrome, photos, Tweetbot, messages, bbedit, Authy, slack, Trello, activity monitor, cyber duck, preview, adobe acrobat. Fired up photoshop and opened a few hundred mb file. Still NO noticeable or loud fan spinning.

I'm happy to look at any settings to try and help!

Hi @pshifrin,

Congratulations! Could you please post the following so that we know the exact settings that worked for you. Thanks a lot.

  1. A screenshot of your display preferences.

    You'd find it in System Preferences.app > Displays > Display tab. Example screenshot below:

    1582724200202.png


  2. A screenshot from "iStats Menus".

    You'd find the immediate values of interest under the "SENSORS" tab in iStats Menues. Example screenshot below:

    1582724458826.png

Thank you.
 
All those programs are low impact programs, sure they take up some ram, but the stress on CPU is minimal.
Depending on your room temp etc, your fans might not be super loud, I'm running at a steady 2k rpm with 60 degree at idle, and don't notice the fans that much in an office environment..
But if I start a virtualbox machine, compile a program, download/sync with gigabit speed or any other heavy cpu load, my temp goes up to 80-100 degrees and fans will ramp up to 5k+ over time.

The system will handle 30w of load of course (your scenario with 20w gpu and 4-7w cpu). But when you start loading the CPU, because the GPU is already pinned at max, the overhead is much smaller. You can consider it the same as running a full blown AAA game title constantly with full GPU and CPU load.

So the issue for me, is that I can't do regular tasks I did previously, on a system that should handle it with ease. If I run without external screens, I hardly ever hear the laptop even under heavy CPU loads as I have 15-20watts of extra headroom on the cooling system.
You nailed it, our rMBP can only handle about 30 watts of heat "budget" without resorting to loud fans. Since the GPU is uselessly consuming excessive power when connected to a 4K+ monitor with scaling enabled, it leaves much less for the CPU to use without triggering fans. Having a bunch of apps loaded taking up memory is not stressful for the CPU.
 
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Hi @pshifrin,

Congratulations! Could you please post the following so that we know the exact settings that worked for you. Thanks a lot.

Thank you.

@gsbabil here you go:

Note that I intentionally have the Laptop screen at native 2x (and did so on my 15 too), yay over 40 eyes!
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All those programs are low impact programs, sure they take up some ram, but the stress on CPU is minimal.
Depending on your room temp etc, your fans might not be super loud, I'm running at a steady 2k rpm with 60 degree at idle, and don't notice the fans that much in an office environment..
But if I start a virtualbox machine, compile a program, download/sync with gigabit speed or any other heavy cpu load, my temp goes up to 80-100 degrees and fans will ramp up to 5k+ over time.

The system will handle 30w of load of course (your scenario with 20w gpu and 4-7w cpu). But when you start loading the CPU, because the GPU is already pinned at max, the overhead is much smaller. You can consider it the same as running a full blown AAA game title constantly with full GPU and CPU load.

So the issue for me, is that I can't do regular tasks I did previously, on a system that should handle it with ease. If I run without external screens, I hardly ever hear the laptop even under heavy CPU loads as I have 15-20watts of extra headroom on the cooling system.

I understand, from skimming this thread I was under the impression that if I was doing "lite" office type work, and connected to a 4k screen, I'd hear it full blast, which was not the case. So I just fired up a very simple Premiere project I had done for a presentation a few months ago, 10 mins long spliced to 1080p videos together and ... then fans did ramp up as expected for a good couple of minutes just from opening premiere and loading the timeline, they eventually slowed down again.
 

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@gsbabil here you go:

Note that I intentionally have the Laptop screen at native 2x (and did so on my 15 too), yay over 40 eyes!
[automerge]1582738629[/automerge]


I understand, from skimming this thread I was under the impression that if I was doing "lite" office type work, and connected to a 4k screen, I'd hear it full blast, which was not the case. So I just fired up a very simple Premiere project I had done for a presentation a few months ago, 10 mins long spliced to 1080p videos together and ... then fans did ramp up as expected for a good couple of minutes just from opening premiere and loading the timeline, they eventually slowed down again.
Again, fans at full speed isn’t the issue. The dGPU using 20w constantly is the issue when this should be closer to 3w when doing light tasks. More watts used = more heat = more potential for high speed fans. Especially if the ambiance of the room is in the mid-high 20s (°c).
 
Again, fans at full speed isn’t the issue. The dGPU using 20w constantly is the issue when this should be closer to 3w when doing light tasks. More watts used = more heat = more potential for high speed fans. Especially if the ambiance of the room is in the mid-high 20s (°c).

The 560x in my 15 was also using 20w in the same general usage though...

Edit: I just grabbed a spare 2016 15 inch with the 455, plugged it into the same monitor and it's showing 24w but both these devices are / were running 10.15.3.

Now this is interesting, plugged in to the same 2016 15 running Mojave and it's drawing 9-10w so is this just a Catalina drivers issue?
 
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@gsbabil here you go:

Note that I intentionally have the Laptop screen at native 2x (and did so on my 15 too), yay over 40 eyes!
[automerge]1582738629[/automerge]


I understand, from skimming this thread I was under the impression that if I was doing "lite" office type work, and connected to a 4k screen, I'd hear it full blast, which was not the case. So I just fired up a very simple Premiere project I had done for a presentation a few months ago, 10 mins long spliced to 1080p videos together and ... then fans did ramp up as expected for a good couple of minutes just from opening premiere and loading the timeline, they eventually slowed down again.


Hi @pshifrin,

Thanks a lot for posting the screenshots. These are very useful.

  1. Regarding the LG UltraFine, could you please click on "Scaled" and confirm the resolution currently in use.

    Please note that you are using 1536 x 960 @ 60 Hz (lower than "Default") on your MBP, which could impact the "Default" resolution in use on the LG, as Catalina tries to provide similar sized UI elements on both of the displays.

  2. Finally, could you please share a screenshot of the "About This Mac" screen.

    This is to confirm the model and hardware configuration on your MBP.
Thanks a lot.
 
## Results under Catalina 10.15.4 Beta 2

I upgraded my MBP-2019 to Catalina 10.15.4 Beta 2 (19E234g) today, and noticed the following changes:
  • "Radeon High Side" is almost always at ~3.0 Wwith or without charging cable attached (screenshot-1 below).
    • If you have a look at my post here, you'll notice that under Catalina 10.15.3 Final, "Radeon High Side" ramains at ~0.10 W most of the time.
  • "Radeon High Side" still reached ~19.5 Wwhen an external 4K monitor is attached (screenshot-2 below).
    • More details on the Dell P2415Q screen, resolution, refresh-rate etc. are here.
Thank you.

## Screenshot 1 (without external monitor)

View attachment 896129

## Screenshot 2
(with external monitor)

View attachment 896130

That's a shame. Hope they fix it in the next OS update.
 
The 560x in my 15 was also using 20w in the same general usage though...

Edit: I just grabbed a spare 2016 15 inch with the 455, plugged it into the same monitor and it's showing 24w but both these devices are / were running 10.15.3.

Now this is interesting, plugged in to the same 2016 15 running Mojave and it's drawing 9-10w so is this just a Catalina drivers issue?

> Now this is interesting, plugged in to the same 2016 15 running Mojave and it's drawing 9-10w so is this just a Catalina drivers issue?

Thanks again for sharing this. We hope you are right and Apple is willing to release a patched driver!

For the new readers on this thread:
  • MBP-2016 15" has the 2GB AMD Radeon Pro 455 discrete graphics processor
    • @pshifrin experiences 24W power draw under Catalina (more heat and fan-noise), but ~10W under Mojave (less heat and fan-noise) while using the same MBP and external monitor.
  • MBP-2019 16" has either of the 4GB/8GB Radeon Pro 5300/5500 discrete graphics processor
    • Most of the MBP-2019 16" users on this thread experience ~20W power draw under Catalina (more heat and fan-noise).
Thank you.
 
Hi @pshifrin,

Thanks a lot for posting the screenshots. These are very useful.

  1. Regarding the LG UltraFine, could you please click on "Scaled" and confirm the resolution currently in use.

    Please note that you are using 1536 x 960 @ 60 Hz (lower than "Default") on your MBP, which could impact the "Default" resolution in use on the LG, as Catalina tries to provide similar sized UI elements on both of the displays.

  2. Finally, could you please share a screenshot of the "About This Mac" screen.

    This is to confirm the model and hardware configuration on your MBP.
Thanks a lot.

The ultra fine is running at "looks like 1920x1080" and the laptop is open with 1536x960 @ 60hz. I prefer the exact 2x retina scaling on my screens, that's what I meant by default sorry for the confusion, ie default for the exact resolution 2x of the display.

The laptop is a stock Apple Store mid-tier model. 2.3/16/1TB/5500m 4GB
 
The ultra fine is running at "looks like 1920x1080" and the laptop is open with 1536x960 @ 60hz. I prefer the exact 2x retina scaling on my screens, that's what I meant by default sorry for the confusion, ie default for the exact resolution 2x of the display.

The laptop is a stock Apple Store mid-tier model. 2.3/16/1TB/5500m 4GB

Hi @pshifrin,

Thanks again for confirming with the details above.

## Results under Catalina 10.15.4 Beta 3

I just upgraded my MBP-2019 to 10.15.4 Beta 3 (19E242d), and can confirm that Radeon High Side power draw is still at ~19.5 W (which follows the extra heat and fan noise).

Thank you.
 
We've just picked up a second MBP, base model and have been using it for the past day with a 4K LG screen and no issues yet, same as with our other 16". 😐
 
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