Physical resolution is not changed - just scaling applied

[abrilevskiy]

I am trying to use Picture by Picture of HP Z27k G3 4K (3840 2160) monitor.
In the picture-by-picture mode the screen is split in parts with half resolution: 1920 x 2160
Despite set 1920 x 2160 or 2160 x 1920 in BetterDisplay - the display detect 4K (3840 2160) as an input signal and just scale picture

[waydabber]

Yes, the app normally lists physical resolutions only and when adding custom resolutions, those will be scaled resolutions. You need to use the Display Mode's filters to get more + might need to enable Unsafe resolutions as well under Settings/Displays/Overall.

Some newer Apple Silicon Macs don't easily allow physical resolution switch (except for some scenarios) - in this case you need to use the betterdisplaycli get -connectionModeListAll feature to determine the recognized physical timings (you can also switch to one but that is a low level switch, won't resize the framebuffer correctly) and might need to set the native resolution to one under Configuration Editing and apply an activate/reconnect. Alternatively you can try setting the mode using the mode number, get it by using betterdisplaycli get -displayModeList.

If you want to use a mode that does not exist in the display's EDID, you might need to edit get the EDID using the app, add the timing via AW EDID Editor and apply the updated EDID so the custom timing will be available.

[waydabber]

Some examples for how to get and set connection modes:

#3229 (comment)

Same for proper (high-level OS enumerated) display modes (mostly scaled, some real but those might not actually switch mode depending on Apple Silicon chip generation):

#2646 (comment)

+ a general help for CLI:

https://github.com/waydabber/BetterDisplay/wiki/Integration-features,-CLI

[waydabber]

Additional note - I plan to add some help for real mode switch as the situation is getting harder and harder in newer macOS versions. #3252