Intel Mac heating up when external monitors are connected

[ginger2016]

Does anyone know why Intel Macs(mine is 2019 model, i9, 16GB RAM, with AMD GPU) heats up when external monitors are connected. My Mac works well when used on its own, but becomes unusably slow when external monitors are connected. I looked all around the web for a fix, none of the fixes succeeded.

[BjoernKW]

It's a well-known problem, for which unfortunately there doesn't appear to be a reliable, one-size-fits-all solution, though, see (including lots of suggestions for potential fixes):

https://talk.macpowerusers.com/t/16-macbook-pro-gets-excessi...

https://forums.macrumors.com/threads/2019-16-is-hot-noisy-wi...

https://www.reddit.com/r/apple/comments/f10ip5/how_to_fix_16...

The culprit is the Radeon High Side GPU power consumption rising to 20W when connecting to an external display.

For some configurations, customising the screen refresh rate (using SwitchResX) seems to work, for others it's connecting the external monitor to another port (and / or not charging via the same port), while yet for others none of those suggestions seems to work.

[brucethemoose2]

It could be powering up the AMD GPU, which normally lies dormant since the internal display is hooked up to the Intel chip, and "stealing" TDP from the Intel CPU.

As someone else mentioned, try another port. On my G14, USB-C is the dGPU and HDMI is the integrated GPU.

[hayst4ck]

When I've plugged power into the left side, it has similar overheating behavior, but the right side seems to have no problems. See if using the ports on the right side of the device solves the issue.