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?

  • Is your monitor plugged in on the right or left?
    – X_841
    Jul 15, 2021 at 6:56
  • Left. Dont tell me that this makes the difference :-D
    – ppt
    Jul 15, 2021 at 7:15
  • 1
    apple.stackexchange.com/questions/363337/… it may actually be the problem.
    – X_841
    Jul 15, 2021 at 9:00
  • 1
    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 5, 2021 at 3:03

4 Answers 4


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!

  • 2
    I tried this - it had no impact on my machine (16" i9 MPB with a single external display).
    – Nathan S.
    Jan 7, 2022 at 5:33

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.


  1. https://dnsmichi.at/2022/01/10/macbook-pro-16-2019-heat-problem-with-external-display/
  2. https://apple.stackexchange.com/a/444119/468509
  • "Defiance"? I may be mistaken, but I don't think that is the correct word. Jul 31, 2022 at 13:42
  • Can you please edit in links to the research you found?
    – agarza
    Jul 31, 2022 at 14:25
  • Edited the post to correct that wrong word and to add sources. Thanks for the suggestions. Aug 1, 2022 at 14:04

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.

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.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .