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New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

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Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#161
post #157

Earlier quoted context omitted.

Out of interest - whats the output of `system_profiler SPDisplaysDataType`?

You can see the result here: https://gist.github.com/PierBover/99f44e5cba1657eb7e4ce8e2aa... I'm on macOS 15.7.4. It's so weird that it says 5120 x 2880 when the ASUS PA329CV is 3840 x 2160.

That's a 404, but if it only says 5120x2880 then you're not running full 4K HiDPI which would show 7680x as per the blog post.

Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#162
post #122
post #64

Earlier quoted context omitted.

I don't expect emails to get through to busy CEOs of huge companies like Apple unless you're really lucky and they make it through some automation, but I have dropped him an email just in case. I guess you never know.

Has anyone tried sending an email to Nadella telling him that Windows is terrible now? What if that was all it took.

Bill Gates couldn't get it done.

https://www.techemails.com/p/bill-gates-tries-to-install-mov...

Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#163

Earlier quoted context omitted.

You may be able to get this working using PBP and 2 cables without virtual displays. This is my write up for using HiDPI@120hz for two 57” G9s on my M2 MacBook. https://www.reddit.com/r/ultrawidemasterrace/s/VrBLFDxYzg

Ah but you see, the challenge is to get a 3-split PBP on an M2 pro on a monitor with a native res of 7680x2160, each one scaled down 33%, working at 120hz with HDR, all hidpi like so: ┌─┐┌────┐┌─┐ │ ││ ││ │ └─┘└────┘└─┘ It creates some wonky math and requires plenty of dock and cable shenanigans and unlocking resolutions above 8k via BD. It's the third "monitor" where it gets tricky with the M2 pro especially at thes…

Fascinating. What's that gain you over using the monitor's native resolution full screen vs PBP mode?

Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#164
post #130

Earlier quoted context omitted.

> From what I understand, the main goal is to fix the problem that non-native (1:1 pixel mapping) resolutions and scaling look worse than native. That would be my instinct as well, but the author seems to be delibarately doing the exact opposite . Trying to force a 2x HiDPI and then downscaling to native display resolution whereas he could have just done a 1:1 LoDPI rendering. What you get in the end is some equivale…

The author said that the problem is that Apple has introduced a size limit for the display (3360x1890) that is lower than the size of the actual display, which is a standard 4k display (3840x2160). So 1:1 rendering can cover only a part of the screen, while the remainder remains unused. If the maximum size limit is used but applied to the entire screen, it does not match the native resolution so interpolation is used…

That does not seem to be the case for my M4 Mac mini in native "low-DPI" mode with a 4K display, so I think the problem only appears in HiDPI (7680x4320 framebuffer downscaled back to 3840x2160 only). The author seems to be confirming the max intermediate framebuffer is 6720 pixels wide.

Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#165
post #48
post #5

This is not a normal retina configuration. This is a highly unusual configuration where the framebuffer is much larger than the screen resolution and gets scaled down. Obviously it sucks if it used to work and now it doesn't but almost no one wants this which probably explains why Apple doesn't care.

To be frank, it's kind of embarrassing if an entry-level Windows laptop with a decent integrated GPU handles this without much effort. Apple is free to make its own choices on priority, but I'm disappointed when something that's considered the pinnacle of creative platforms sporting one of the most advanced consumer processors available can't handle a slightly different resolution.

Nope, no windows laptop will render to an 8K framebuffer then downsample that by 2x in each direction to display it at 4K. That’s what the OP is complaining that MacOS won’t let him do.

Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#166

Earlier quoted context omitted.

Fine, you made me look it up. M1 Air defaults to 2880x1800 on a 2560x1600 display, which is a 1.125x scaling. Nowhere near the 1.5x you claim.

2560 x 1664 is the resolution of the latest M5 Air. The default UI is 1470 × 956. "More space" is 1710 × 1112. When you set it to "more space" it becomes noticeably slower, but not blurry.

Those numbers of 1470x956 are “points” or “looks like” values, not the size of the frame buffer. The frame buffer for “looks like 1470x956” is exactly 2x that, or 2940x1912. On a 2560x1664 display, that’s a 1.148x scale factor. Again, nowhere near 2x, even on the “more space” setting.

Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#167
post #130

Earlier quoted context omitted.

> From what I understand, the main goal is to fix the problem that non-native (1:1 pixel mapping) resolutions and scaling look worse than native. That would be my instinct as well, but the author seems to be delibarately doing the exact opposite . Trying to force a 2x HiDPI and then downscaling to native display resolution whereas he could have just done a 1:1 LoDPI rendering. What you get in the end is some equivale…

The author said that the problem is that Apple has introduced a size limit for the display (3360x1890) that is lower than the size of the actual display, which is a standard 4k display (3840x2160). So 1:1 rendering can cover only a part of the screen, while the remainder remains unused. If the maximum size limit is used but applied to the entire screen, it does not match the native resolution so interpolation is used…

Nope, you completely misread the post. All Mac’s including M4s and M5s can run at a 1:1 4K resolution all day long filling the screen completely. That’s not what the OP wanted though, they wanted to render at 8k (roughly 7680 px by 4320 px), then downsample that by 2x in each direction to map to the 4K display. Supposedly to make things “look better” than rendering at the native resolution but it sounds insane to me.

Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#168
post #33

I use a 4K 32'' Asus ProArt monitor and didn't notice any difference between my M2 Pro and my M4 Pro (on Sequoia). I will admit my eyesight is not the best anymore but I think I would notice given I'm a bit allergic to blurry monitors. Anyway I will run the diagnostic commands and see what I get.

I use a 4K 45" Aorus (Gigabyte) on M4 and M2 Pro — also eyesight/age...

Both will run at 144Hz, but the M4 will occassionally flicker if you're close to limits on dual-screens. I set to 120Hz and don't notice any difference.

----

My M4 complaint is that I can no longer update my OS with a USB Installer offline. My M3 (and lower) will, using the same Sequoia media.

Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#169
post #148
post #89

This might be a dumb question: Is the author looking to run 4k display at HiDPI 8k framebuffer and then downscale? What's the advantage of doing so versus direct 4k low-DPI? Some sort of "free" antialiasing?

i'm also using https://betterdisplaymac.com/ for this purpose. even on a native 2K monitor, having a virtual 5K frame buffer downscaled to 2K yields perfectly enjoyable results, compared to how macOS' native 2K image would look like; it causes eye-bleed :)

Assuming by 2K you mean 2560x1440, I also prefer non-integer HiDPI 2560x1440 mode over both native and HiDPI 1080p modes on my large (55”) 4K display, and the non-integer scaling is only rarely a problem.

Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#170

Earlier quoted context omitted.

Ah but you see, the challenge is to get a 3-split PBP on an M2 pro on a monitor with a native res of 7680x2160, each one scaled down 33%, working at 120hz with HDR, all hidpi like so: ┌─┐┌────┐┌─┐ │ ││ ││ │ └─┘└────┘└─┘ It creates some wonky math and requires plenty of dock and cable shenanigans and unlocking resolutions above 8k via BD. It's the third "monitor" where it gets tricky with the M2 pro especially at thes…

Fascinating. What's that gain you over using the monitor's native resolution full screen vs PBP mode?

I hate spending any unnecessary clicks or keyboard shortcuts on getting whats out of my head into the computer. I used yabai before primarily, now using aerospace. Since the monitor is super ultra-wide (57 inches with a very high DPI) the native resolution makes everything ultra small to my eyes. It's the same height as my 34-inch Samsung G5s which are 1440 pixels tall natively, but since this one is 2160, it would have to be 1.5 times larger physically to look decent at native res especially on macOS. The only other option is to scale the UI 1.5x which is where all the problems begin.

I like the three-column separate monitor layout because I have hotkeys, primarily driven by my mouse but also usable keyboard-only where I can easily switch between monitors with `⌘+`` which moves my cursor between them. I can select whichever monitor I want and put my mouse to it, and I can switch to any workspace on any monitor quickly. I also have hotkeys that sync three workspace numbers across monitors, so switching between them switches all AeroSpace workspaces on all three monitors simultaneously. If I have five projects going, I'd have the terminal on the left, Linear and other communication tools on the right in accordion mode with AeroSpace, and I can use my mouse or keyboard exclusively to find exactly what I'm looking for almost as fast as I think of it. I spend zero time on window management or organization now so it makes it thoughtless to use.

If I'm just using the monitor's native resolution there's no real way to do portals — having two apps open as sticky and only switching a portion of the monitor space to a different app while keeping the other sticky. There are hacks you can do with AeroSpace, especially since AeroSpace doesn't use native macOS Spaces, but the three-monitor layout is a much more robust approach in my opinion just a bit of a nightmare to setup. Theres a million little mac annoyances you have to fix.

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