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f1r3s4l3 Author

Level 1

30 points

Space-switching lags when app is fullscreen on other display

I recently switched to a 14" M1 Max with 64GB of RAM and noticed something rather strange, that I didn't have on my M1 Max 32GB model.

Setup was and is as follows:

M1 connected by USB-C to a Samsung LC34 screen (3440x1440).

Since I got the new Mac running, whenever I set an app to fullscreen on the Mac itself, I get extremely laggy visuals when switching spaces on the big external screen. Sometimes even the mouse lags terribly for a few seconds. As soon as I end fullscreen, everything is smooth again.

Has anyone stumbled across this before? As it wasn't there on my "old" M1 I suppose (read: hope) it must be some kind of setting I'm missing.

MacBook Pro Apple Silicon

Posted on Jul 4, 2022 10:07 PM

Top-ranking reply

f1r3s4l3 Author

Level 1

30 points

Posted on Jul 5, 2022 4:45 AM

And another one I found out on my own :)

Looks like ProMotion is the culprit. When I set the internal display to 60Hz fixed, everything is fine.

With ProMotion enabled the stuttering occurs.

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Space-switching lags when app is fullscreen on other display

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