Some higher HiDPI resolutions are not available in macOS 27 developer beta 3

[ethank]

I'm on the 5.0.0 alpha, but was the same on the prior stable version. MacOS 27 Beta 2 worked fine. No scaling shows up even when enabled. I attempted to reset the settings, re-enable and reboot with no joy.

[waydabber]

Can you show me how the Display Mode section looks like?

note: scaling slider generally seems to work fine here with dev beta 3 on an M3 Max - or is this about the stricter limit (regression?) in scaling limits in dev beta 3 - while scaling otherwise works fine?

[ethank]

The scaling slider disappeared for me basically. I'm able to do more fine grained on the LG display, but not anymore on the XDR

[waydabber]

Hmm. Isn't the scaling slider the same as the resolution slider? It seems to be present on your original screenshot. Or am I missing/misunderstanding something? :)

The display mode resolution list seems fine.

[ethank]

I used to have the ability to scale the UI separately from the resolution? I lost flexible scaling basically. I used to be able to set UI scaling independently of the resolution?

[waydabber]

Hmm. MacOS supports raster scaling and does not support vector scaling, so you can't change the UI size independently of the video memory (framebuffer) resolution - but you can do so independently of the output resolution. The app's Resolution slider normally does not change the output resolution (the video signal sent to the display), it only changes the scaled resolution, so no matter what you choose, the output still be the native resolution of the display.

[ethank]

Its super strange, because before this beta, I was able to get the UI sizes to match between my 27 and 32" displays, but now it won't do it. I swear there was a way to do HiDPI scaling above 3072x1728 on the 32" displays.

[waydabber]

Ok, this is a macOS 27 beta 3 issue I think, this limits scaling on many displays according to reports. Sadly there is no way around these limits.

[ethank]

I submitted it to Apple as a regression bug.

[cyntler]

I have the same problem after Beta 3 update. Beta 2 was fine.

[waydabber]

I can confirm this. Even on an M3 Max, with the SDXDR I had resolutions available up to 3840px, now it's capped at 3072px.

What's an interesting change is that the M3 Max now seems to show the same IOMFBMaxSrcPixels structure as previously the M4 and M5, meaning it seems to have separate pipe configurations for displays of various sizes. This means that M3 now seems to have the limitations as the M4 and M5 Macs.

on the screenshot one can see the width limits for various configurations - 0x1800 is 6144px (3072px HiDPI) and 0x1e00 is 7680px (3840px HiDPI), depending on the pipe configuration selected for the given port/display.

[riDuxd]

Yeah my M2 Max MBP is also capped at 3072px. Let me know how I can help.

[waydabber]

Can you check what limits you see under "Display Information..." for the display?

If it looks something like this, then the change is applied to M2 Macs as well:

[cyntler]

@waydabber I have M2 Pro MBP and I see this:

[waydabber]

Right, it's the same then.

[riDuxd]

Yep same for here:

[ethank]

Mac M3 Ultra Studio

[cyntler]

@waydabber Should it be fixed in the near future or will there be a problem with it for a long time?

[waydabber]

DCP display scaler pipe configurations and scaled resolution limits are hard coded into the DCP firmware, there is no known way to fix that. Hopefully Apple addresses this issue - as many rejoiced about improved limits in previous macOS 27 betas...

[riDuxd]

Idk if Apple will listen but I submitted a feedback anyways..

[ethank]

I was hoping this second Beta 3 would fix it, but no :(

[adisor19]

Just installed the public beta and hit this exact same issue.. While I can appreciate the increased sharpness, it really bothers me to have less things fit on my 5k displays as well as on my 16" MBP :/ Really hope Apple will revert this change soon.

[cyntler]

Yes, public BETA has the same problem... unfortunately.

[ethank]

Any word if beta 4 fixed this?

[riDuxd]

Any word if beta 4 fixed this?

It did! :D

Though ignore the UI since I am using NTSC refresh rate. The 60hz in the UI are 144hz, and here are the allocation units if it helps.

[cyntler]

I can confirm. On Beta 4 it works but for me only if I use 144Hz refresh rate. For 165Hz, the maximum of HiDPI resolution is smaller.

[ethank]

Only issue I'm now seeing is clicking the menu and displaying it is really slow in the 5.0.1 alpha.

[waydabber]

Hmm. You mean the app menu? Can you make a screen recording (shift+command+5)? What Mac model are you using?

[ethank]

Screen.Recording.2026-07-22.at.6.51.55.AM.mov

[waydabber]

Uhh, that does not seem normal. How does the memory pressure chart and memory usage for BetterDisplay looks like in the Memory tab of Activity Monitor? It might be that the app simply does not have enough memory to work with somehow? Do you have this issue with the v5.0.0 version?

Can you please try rebooting and check whether this happens before or without any other apps running?

[ethank]

Had it with 5.0.0. This machine has 256GB of RAM, Mac Studio M3 Ultra. I'll do a memory pressure and spin dump on it.

[waydabber]

Hmm. Well, that doesn't seem to be underpowered to me. Yes, please do a spin dump, I may be able to figure out what is happening from that.