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It seems common for MacBookPros2018 overheating when connected to external display (see other info about the general problem here, or here).

Despite there is no risk for HW, it's quite uncomfortable for who works on them.

I noticed that if I connect my MBP to an external display when it runs with battery, it does not get (so) hot.

I suppose that the MBP uses another configuration of its graphics framework when it is not connected to power adapter. Therefore, I hypothesize that if it used the same graphics configuration when it's plugged to the power, then the overheating would be reduced.

Is there a way to make the MPB use the same graphics configuration for external displays also when it is connected to the power?

floatingpurr
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  • My Macbook pro is 2016 and if I am using an external screen then I close the laptop... But if you want both screens open that may not help... – Solar Mike Mar 19 '19 at 12:31
  • Despite the overall problem is the same, this time I asked a way to switch graphics config when MPB is connected to power and to monitor. I do not believe it is a duplicate, indeed the answer provided here focused on different topics – floatingpurr Mar 19 '19 at 13:04

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The 2018 15" MacBook Pros all have dual-GPUs. The AMD GPU is required to be active when an external screen is connected. There is no way to use the internal (Intel) GPU for external screens.

Fan noise is one of the main nuisances of the recent MacBook Pros in my opinion. When I get too frustrated, I sometimes use Turbo Boost Switcher, which helps a bit. Volta is a similar App, but does not seem to work with 2018 MacBooks. Both Apps deactivate the CPU's Turbo Boost mode, which means less speed, but also less power consumption and less noise.

Update: I forgot to mention AppTamer; another tool which often saves me some noise.

n1000
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Is there a way to make the MPB use the same graphics configuration for external displays also when it is connected to the power? ...I noticed that if I connect my MBP to an external display when it runs with battery, it does not get (so) hot.

No. Your MacBook's processor uses Intel SpeedStep technology (including the current 8th gen models) that reduces power when connected to battery to slow things down to increase battery life. This is why it's less hot.

When you connect an external monitor it will use the discrete GPU, so there's no getting around that; this can't be reconfigured.

(IMO), Apple has reached the threshold of where it can take function following form. Because of this, I have modified my behavior and expectations of what their "mobile workstations" (aka MacBook Pros) are capable of delivering. I personally use an Air, old Pro, or a plain MacBook and off load my heavy lifting to the cloud.

Allan
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  • I see, but my MBP gets really hot even when it is connected to an external monitor and the screensaver starts. That's crazy! – floatingpurr Mar 19 '19 at 12:33
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    Screensavers are notorious for consuming tons of CPU. Also, I don't recommend using utilities to slow down your CPU and/or your fan. This makes no sense to me that one would purchase something only to intentionally handicap it so as to not use it to its full potential. – Allan Mar 19 '19 at 12:36
  • I understand your viewpoint. Although, I find crazy that when I use the MBP+external screen with just Word + a Web browser it runs at 60° – floatingpurr Mar 19 '19 at 12:44
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    60°C is well within spec. Apple has set the expectation that laptops should be silent, but with all their magic, they can't circumvent the laws of physics - moving electrons generates heat and heat needs to be dissipated. A machine that makes no (fan) noise will be horrible at dissipating heat. If you're going to use one of those utilities, configure it so it cranks the fan up to 100%. – Allan Mar 19 '19 at 12:50
  • Thank you @Allan for your observations and suggestions! :) – floatingpurr Mar 19 '19 at 12:56
  • The MBP 2015 also gets very hot when connected to an external monitor, even if the MBP 's screen' s back-light is off. When it's plugged in (power) it can get hotter because of the heat that's generated by the power supply and the battery that (maybe) is charging (which also generates a lot of heat). The GPU's are generating a lot of heat as well and even with the fans at max speed, it is not going to make the MBP feel cooler. – Dakta Mar 19 '19 at 12:58
  • When I say 'fans' I actually mean 'fan'! I have an MBP motherboard (13") on my desk and there's only 1 fan on it! – Dakta Mar 19 '19 at 13:14
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The fan system is the thing that goes in a curve on the picture. fan on MBP

Dakta
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