14

Problem

My Macbook overheats insanely.

After investigating a bit, I found out that the correlation is extremely strong with having it plugged in to an external monitor with the Macbook Pro monitor also active.

If I unplug the laptop, or use only the external monitor (i.e. Mac in a 'clamshell' mode), the heating stops within a minute.

I managed to use a software (sudo powermetrics --samplers smc |grep -i "CPU die temperature") to measure this:

  • Indoor temperature: 23C
  • CPU heat without external monitor: 55C
  • CPU heat with external monitor + macbook monitor on: 95C (fan turns on)
  • CPU heat with external monitor, macbook closed: 62C

Details of hardware

  • Macbook Pro (16-inch, 2019). 2.3 Ghz 8-Core Intel Core i9, 16 GB 2667 MHz DDR, AMD Radeon Pro 5500M 4GB, Intel UHD Graphics 630 1536 MB
  • macOS BigSur 11.4
  • Monitor: HP E233. 23-inch (1920 x 1080)
  • Cables connecting: UGREEN USB C Hub HDMI USB C Adapter with 4K HDMI, 3 USB 3.0, SD/TF Card Reader (https://www.amazon.de/gp/product/B07RRPS5NT/), and then a standard HDMI-cable

Tried fixes that didn't work

  • Restart
  • SMC reset
  • Never use two monitors (works)

How could I fix this so I can use two monitors also in the future?

ppt
  • 261
  • Is your monitor plugged in on the right or left? – X_841 Jul 15 '21 at 06:56
  • Left. Dont tell me that this makes the difference :-D – ppt Jul 15 '21 at 07:15
  • 1
    https://apple.stackexchange.com/questions/363337/how-to-find-cause-of-high-kernel-task-cpu-usage/399321#399321 it may actually be the problem. – X_841 Jul 15 '21 at 09:00
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    That trick used to fix the issue in previous versions (I had a 15" 2016 where it worked), but not anymore. I've tried both sides and now it doesn't. I have an i7 and an i9 (both late 2019) and the issue only affects the i9. – t3b4n Sep 05 '21 at 03:03

4 Answers4

2

Try this:

  1. Update to latest macos Monterey
  2. Go to Settings -> Battery => Check the Low power mode both for Battery and Power adapter
  3. On using two 4k monitors, if possible use ports on left/right foreach monitor

Good Luck!

Jaff
  • 21
1

As a MacBook Pro owner, I had the same problem. After a lot of researching, I discovered that our MacBooks have an architectural error: when plugged, an external monitor is always controlled by the dedicated GPU (the AMD Radeon, in my case).

So, as the dedicated GPU is more power-consuming and tends to heat more than the integrated one, our laptops are always overheating when connected to an external monitor.

Sources:

  1. https://dnsmichi.at/2022/01/10/macbook-pro-16-2019-heat-problem-with-external-display/
  2. https://apple.stackexchange.com/a/444119/468509
Emilio Dalla Torre
  • 11
0

try this:

  1. go to [System Preferences] -> [Displays];
  2. go to [Displays Settings] if you are using both built-in monitor and external monitor, otherwise there is not [Displays Settings] and you will see the detail info of the current monitor instead.
  3. remember the Color Profile of the built-in monitor. set the external monitor's Color Profile to the same as the built-in one.
Tyler Xue
  • 1
0

In my case, the culprit was a mismatch between the frame rates of external and built-in displays (50 and 60 Hz, respectively). Setting the external display to 60 Hz in System Settings > Displays solved the problem.

agarza
  • 2,274
perico
  • 1