5K2K at 120Hz with Mac Mini M4

[2xmos]

I went as far as purchasing a Studio M2 thinking it would fix my issues but even tho yes, I get 3840x1620 HIDPI in PBP I ran into so much issues that wasn't worth it:

-The color scheme between the two side of the monitors aren't the same, even with the same color profile

-The only resolution on the 11:9 that match the size of 3840x1620 (size as in, I can drag the mouse on the two monitors/arrange at the same height) in 11:9 is 1920x1620.. The issue? It's way lower quality: Why???????? It's the exact same ratio as 22:9 but with just less space!! And even if I was ok to use another one, none of them are high quality either apart the very low resolutions ones

How does that even happen? Do they have a checkbox "ok we will offer this resolution but it will be ugly"? This one is baffling, I cannot make ANY sense of it the resolution is at the correct size, so why is it low quality?

-There is no utility such as FancyZones on Windows that support not having the "display use separate spaces"

These two make it a deal breaker and the worst thing is: They wouldn't happen if there wouldn't be a stupid arbitrarily limitation on the framebuffer, if there was not I could simply push full resolution on one monitor

I very honestly think anyone responsible for this extremely poor support should be fired at this point.

Meanwhile: I hooked up my monitor to my Windows machine: Tada, works with no PBP workaround, no HDMI or DisplayPort adapter, no weird settings to do

This very extremely poor support of external monitors might make me switch OS at this point, I spent too much efforts into it, days and days of messing with workarounds and such and I didn't even list other random issues that arise such as:

-Coming back from sleep mode sometimes the 3840 x 1620 resolution is not available anymore and u gotta restart the whole mac for it to show up again
-Mac forgetting ur display settings sometimes after boot, so u end up with the left side of monitor being on the right and such randomly

Etc

 

[CedricT]

Hi all,
I'm planning to buy a 5K2K monitor to use with my Mac mini M4 (the base version), and I'm trying to avoid any potential scaling issues — particularly the kind where HiDPI 3840x1620 mode is not available or text appears blurry.
I've read that LG monitor(40WP95C) which I wanted to buy in the first place has these problems. Does anyone have experience with the Dell U4025QW or similar displays? Does it work well with macOS in terms of scaling, HiDPI support?
Thanks for any insights!

edit: just to clarify more: This will be for office work only and multitasking — I don’t need any gaming features etc, just a large screen with a 21:9 aspect ratio and proper macOS compatibility.

Yes, U4025QW works very well out of the box with no tinkering. 3840x1620 HiDPI.

 

[Daydog]

No problem with 3840x1620 on Dell U4025QW 👍

 

[waydabber]

I just noticed that Apple added the following disclaimer to the bottom of the specs page recently:

"Available scaled resolutions for external displays in System Settings > Displays may vary by available system resources and type of connected displays. Scaled resolutions above the macOS default are not reflected in the maximum support listed above."

https://support.apple.com/en-us/102194 (under "Maximum Display Support")

This seems to specifically to address issues/complaints regarding M4 Macs and the dynamic nature of framebuffer size allocation (explained here: https://forums.macrumors.com/threads/5k2k-at-120hz-with-mac-mini-m4.2441289/post-33758270).

 

[roman.stapunov]

https://support.apple.com/en-us/102194 (under "Maximum Display Support")

🤣 so seems apple doesn't want to fix the issue they introduced. M2 pro and m3 pro have enough resources to drive Dell u4021qw at 3840x1620 + dell up27020q at 2560x1440 and own display at good resolution. What happened with m4 pro?

Why m4 can run u4025qw at 3840x1620 120Hz, but can't u4021qw 60Hz without Better Display hack?

This is definetly a bug or lock in the OS and has nothing to do with mac resources. Only issue I believe is with quality of Apple resources writing this ***** code

 

[kong0329]

🤣 so seems apple doesn't want to fix the issue they introduced. M2 pro and m3 pro have enough resources to drive Dell u4021qw at 3840x1620 + dell up27020q at 2560x1440 and own display at good resolution. What happened with m4 pro?

Why m4 can run u4025qw at 3840x1620 120Hz, but can't u4021qw 60Hz without Better Display hack?

This is definetly a bug or lock in the OS and has nothing to do with mac resources. Only issue I believe is with quality of Apple resources writing this ***** code

Agreed. But remember. Apple is like a sinking titanic.. No one wants to join Apple anymore, and it's becoming a big tech version of coca-cola. (Hey Apple fanboys. We are releasing cherry-flavor... no cherry-color iphone in 2025!)
I'm pretty sure whoever was in charge of writing firmware to support hidpi for 3840x1620 left the company, and now nobody in the team is willing to or is capable of writing a code (or asking Cursor to write a code) to fix this.

 

[waydabber]

🤣 so seems apple doesn't want to fix the issue they introduced. M2 pro and m3 pro have enough resources to drive Dell u4021qw at 3840x1620 + dell up27020q at 2560x1440 and own display at good resolution. What happened with m4 pro?

Why m4 can run u4025qw at 3840x1620 120Hz, but can't u4021qw 60Hz without Better Display hack?

This is definetly a bug or lock in the OS and has nothing to do with mac resources. Only issue I believe is with quality of Apple resources writing this ***** code

It don't think this is a bug, and it is probably related to resource allocation - if you connect a 5K2K screen with 60Hz, then according to the specs page the mini should still be able to allocate resources for an additional 8K display or two additional 6K displays - so it needs to reserve those resources (just in case) and allocate the required minimum for your display. But if you connect a 5K2K screen at 120Hz, the Mac does not have to reserve those resources for all these potential additional displays to meet any listed specs, so it can safely fall back to a max supported 2 display config - in which it knows it will not need all those extra resources, therefore it can then give more away to the 5K2K 120Hz display to have a larger framebuffer.

Sadly there is no way to convince your Mac that you don't want to have any additional displays connected and it should give all resources to your single display. Apple could in theory tweak how this resource allocation works but by now it is safe to say, they decided against changing stuff (any real improvement would probably need a UI for power users where the user can configure stuff for themselves in detail and then reconnect the displays - but average users would not really understand all these scaled vs native resolution and HiDPI-LoDPI stuff so it is understandable they did not want to go that way).

 

[Chancha]

It don't think this is a bug, and it is probably related to resource allocation - if you connect a 5K2K screen with 60Hz, then according to the specs page the mini should still be able to allocate resources for an additional 8K display or two additional 6K displays - so it needs to reserve those resources (just in case) and allocate the required minimum for your display. But if you connect a 5K2K screen at 120Hz, the Mac does not have to reserve those resources for all these potential additional displays to meet any listed specs, so it can safely fall back to a max supported 2 display config - in which it knows it will not need all those extra resources, therefore it can then give more away to the 5K2K 120Hz display to have a larger framebuffer.

Sadly there is no way to convince your Mac that you don't want to have any additional displays connected and it should give all resources to your single display. Apple could in theory tweak how this resource allocation works but by now it is safe to say, they decided against changing stuff (any real improvement would probably need a UI for power users where the user can configure stuff for themselves in detail and then reconnect the displays - but average users would not really understand all these scaled vs native resolution and HiDPI-LoDPI stuff so it is understandable they did not want to go that way).

Is this specifically described in the "pipe horizontal limit values 3360 (6270), 3840 (7680)" in BD?
So this perimeter is visible even to 3rd party but you are saying there does not seem to be a way to actively engage one or another?

 

[roman.stapunov]

It don't think this is a bug, and it is probably related to resource allocation - if you connect a 5K2K screen with 60Hz, then according to the specs page the mini should still be able to allocate resources for an additional 8K display or two additional 6K displays - so it needs to reserve those resources (just in case) and allocate the required minimum for your display. But if you connect a 5K2K screen at 120Hz, the Mac does not have to reserve those resources for all these potential additional displays to meet any listed specs, so it can safely fall back to a max supported 2 display config - in which it knows it will not need all those extra resources, therefore it can then give more away to the 5K2K 120Hz display to have a larger framebuffer.

Sadly there is no way to convince your Mac that you don't want to have any additional displays connected and it should give all resources to your single display. Apple could in theory tweak how this resource allocation works but by now it is safe to say, they decided against changing stuff (any real improvement would probably need a UI for power users where the user can configure stuff for themselves in detail and then reconnect the displays - but average users would not really understand all these scaled vs native resolution and HiDPI-LoDPI stuff so it is understandable they did not want to go that way).

I can accept that Apple developers from the another planet when they have own way of setting requiriments and brake things that worked before. But assuming you are right why u4025qw works perfectly fine but u4021qw doesn't?

There is specs from apple site for mac mini:

How can I understand that I need 5k2k 120hz monitor to get more scaling resolution options?

If this is not a bug, then why everything works fine via software tools via mirroring Virtual display? It is more resource consuming.

Anyway we can't change way Apple doing things, but this one another thing forcing me looking alternative hardware and software for my workflow.

 

[WhisperingBobcat]

It don't think this is a bug, and it is probably related to resource allocation - if you connect a 5K2K screen with 60Hz, then according to the specs page the mini should still be able to allocate resources for an additional 8K display or two additional 6K displays - so it needs to reserve those resources (just in case) and allocate the required minimum for your display. But if you connect a 5K2K screen at 120Hz, the Mac does not have to reserve those resources for all these potential additional displays to meet any listed specs, so it can safely fall back to a max supported 2 display config - in which it knows it will not need all those extra resources, therefore it can then give more away to the 5K2K 120Hz display to have a larger framebuffer.

Sadly there is no way to convince your Mac that you don't want to have any additional displays connected and it should give all resources to your single display. Apple could in theory tweak how this resource allocation works but by now it is safe to say, they decided against changing stuff (any real improvement would probably need a UI for power users where the user can configure stuff for themselves in detail and then reconnect the displays - but average users would not really understand all these scaled vs native resolution and HiDPI-LoDPI stuff so it is understandable they did not want to go that way).

OK, maybe not a bug, but a crap implementation. My i5 2018 Mac mini works better with my 5k2k/60 monitor than my M4 2024 Mac mini. It is pitiful.

An advance UI? How about one checkbox saying "Enable optimal resolution(s) and display settings for this monitor." and a warning that says I won't be able to connect more than one additional monitor. Easy. Then let me have the resolutions that were available in the Intel days.

They just don't care, and have more important things to work on, like AI generated memojis. "Forget" those who won't buy a pair of $1500 Studio Displays for a $500 computer.

I knew about this before I bought, and am angry at myself for my purchase and my naivety, thinking that they would care enough to fix it.

 

[roman.stapunov]

Finally I gave up on this issue and sold my Mac mini m4 24/512. Via Virtual display quality is not the same as without and after sleep it may start flickering, so you have to disable and enable Virtual Display, sometimes few times, to fix it. Better Display has option to adjust available resolution without Virtual Display, but for m4 it brings very small improvement. Based on search via google I assume this should work for m4pro/m4 max perfectly fine.

This is link to the proposed solution https://github.com/waydabber/BetterDisplay/wiki/Fully-scalable-HiDPI-desktop. If anybody with m4 pro/max can check and tell will be useful for people who is in decision mode. I regret not buying mini m4 pro right away.

Finally I decided to purchase MacBook Pro 16 m3 Max base. I found it on a very good sale in my location, so I added just $1.5k after selling Mac mini and now I am absolutely happy with my Dell u4021qw. Dell u4025qw costs $3k in my location and it is not easy to sell old one, so I am waiting M6+ for now as M3 Max is extreme horse power solution that will serve me for a long time. May be in time of M6/M7 I will be ready to buy new monitor )

 

[ClassicMartini]

Fine.

I'll take another bullet for the team...

LG 45GX950A-B.AAU - 45” Ultragear OLED: aka "GX9".

Using the USB-C (thunderbolt?) cable provided in box, to the thunderbolt port on back of M4 Max Studio.

My odd assortment of monitors, collected over the years.

So, that's two 5k 2k monitors, and one 3440 x 1440.

 

[roman.stapunov]

So it proves, that issues with 5k2k 60Hz monitors. If you have 120Hz+ then should have proper scaling options, at least m4 pro/max.

 

[Chancha]

Fine.

I'll take another bullet for the team...

LG 45GS96QB-B 45” Ultragear OLED: aka "GX9".

Using the USB-C (thunderbolt?) cable provided in box, to the thunderbolt port on back of M4 Max Studio.

View attachment 2527637

My odd assortment of monitors, collected over the years.
View attachment 2527638

So, that's two 5k 2k monitors, and one 3440 x 1440.
View attachment 2527639

Do you mean the new 5k2k OLED? Which should be the 45GX950A-B instead? 45GS96QB-B is the 1440 one. But yeah really great news if this is the case, at the moment it is the GOAT ultrawide simply due to the fact of being OLED.

 

[ClassicMartini]

Do you mean the new 5k2k OLED? Which should be the 45GX950A-B instead? 45GS96QB-B is the 1440 one. But yeah really great news if this is the case, at the moment it is the GOAT ultrawide simply due to the fact of being OLED.

LG UltraGear™ 45-inch OLED Dual-Mode 5K2K Gaming Monitor | 0.03ms (GtG), Rich Bass (10Wx2), DisplayHDR True Black 400, DP 2.1 & USB-C | LG AU

LG UltraGear™ 45-inch OLED Dual-Mode 5K2K Gaming Monitor | 0.03ms (GtG), Rich Bass (10Wx2), DisplayHDR True Black 400, DP 2.1 & USB-C

www.lg.com

 

[2xmos]

So it proves, that issues with 5k2k 60Hz monitors. If you have 120Hz+ then should have proper scaling options, at least m4 pro/max.

I don't think so, I have a G9 57" that I put in PBP, so the left side is 5K2K 120 Hz and on my M4 Pro I don't have proper scaling
My M2 Max run without issue tho

 

[roman.stapunov]

G9 57" is 8k2k resolution. I believe this is the reason of the issue with m4. Even when you use split view mode.

But good to know that it works fine with M2 max. I assume should work fine with M3 max as well. I thought to buy 8k2k Samsung or Acer as it has the same price in my location as dell u4025qw

 

[2xmos]

G9 57" is 8k2k resolution. I believe this is the reason of the issue with m4. Even when you use split view mode.

But good to know that it works fine with M2 max. I assume should work fine with M3 max as well. I thought to buy 8k2k Samsung or Acer as it has the same price in my location as dell u4025qw

I'm talking about PBP mode which split the screen into a 5K2K and a smaller one (21:9 and 11:9), not the full resolution
I actually have to do that (connect it in PBP to have two monitors) cause there is no HiDPI resolution fitting for the full resolution at all

 

[waydabber]

Is this specifically described in the "pipe horizontal limit values 3360 (6270), 3840 (7680)" in BD?
So this perimeter is visible even to 3rd party but you are saying there does not seem to be a way to actively engage one or another?

Yes. There are numerous places in the system where the framebuffer (where the source of the displayed image is stored in the memory) size limits and pixel clock limits are visible (note: the latest internal pre-release version of BetterDisplay will show these under the connection mode as well). This can be extracted from some entries in the I/O registry tree and also there are some APIs that can report this. For example here you see a 4K display, that has 3072px HIDPI (6144px) assigned to it horizontally as max source resolution, all scaled modes have to be inside these width and height limits (there is also a bandwidth limit applied for the source).

The way the display output is produced from the framebuffer is implemented in a very low level, so it's not just that macOS can composite a desktop of any size and then rescale it to the required output (note: this happens with virtual screens, that's why the size limitation does not affect those - but virtual screens obviously do not have to be as efficient and flexible as a native display - which must support all kinds of HDR modes, high refresh rates, VRR etc).

I hope this somewhat clarifies the issue, and why it is that there seem to be no way to get around these limitations with some software hack (at least this is how it looks to me based on all I know).

 

[ClassicMartini]

Do you mean the new 5k2k OLED? Which should be the 45GX950A-B instead? 45GS96QB-B is the 1440 one. But yeah really great news if this is the case, at the moment it is the GOAT ultrawide simply due to the fact of being OLED.

Not to appear like an LG fanboy, or slipping into advertising territory.... Yes, it is GOAT level.
Best of both worlds (for now):

OLED and crispy text, thanks to fixing the sub-pixel layout.
-
I'm generally happy with high bitrate 1080p for media consumption, but now have a compelling reason to go 4k.

Did a re-watch (and side by side comparison of 1080p vs 4k) of a few key scenes/episodes from The Expanse.
The effects of the star field backgrounds, inky black space punctuated by the stars of the cosmos. Just, wow.
-
Also... The speakers are actually decent. Admittedly a low bar to cross with monitor speakers...
-
Not blow your socks off hi-fidelity - the cognoscenti have already identified the headphones in the pic above - but more than sufficient to watch a movie with my children (there's a couch to the left of the table that I can maneuver the monitor around to).
-
The 800r curve will be the stumbling block for most. I've recalibrated (my brain), but I honestly think 1000r - 1800r would've made this an easier sell for more people.

 

[kasakka]

G9 57" is 8k2k resolution. I believe this is the reason of the issue with m4. Even when you use split view mode.

But good to know that it works fine with M2 max. I assume should work fine with M3 max as well. I thought to buy 8k2k Samsung or Acer as it has the same price in my location as dell u4025qw

MacOS treats the 57" G95NC as two separate monitors if you use Picture By Picture mode.

On my M2 Max MBP 16" I can run:

• Samsung G95NC split 1: 5120x2160 @ 120 Hz w/ HiDPI 3840x1620.
• Samsung G95NC split 2: 2560x2160 @ 120 Hz w/ HiDPI 1920x2160.
  • 120 Hz inexplicably only works if this side is connected via Displayport. HDMI 2.1 is limited to 60 Hz but works fine at 120 Hz if the split is set to 4K + 4K. MacOS doesn't seem to quite know what to do with an oddball 2560x2160 res.
• Samsung G70A 4K 144 Hz: 3840x2160 @ 144 Hz w/ HiDPI up to 3008x1692

All these work at the same time. What does not work is single input 7680x2160, it maxes out at 3840x1080 HiDPI scaling which is so stupid. PbP must be used to get around these limitations.

If the M4 Max does not allow for this, then it's a clear step back in ability. M4 Pro might be less capable, which is very non-obvious when Apple's own display support specs are so incredibly vague.

 

[bassjunky]

Consider the bandwidth for each mode:

edid-decode -S --cvt w=3840,h=2160,fps=60,rb=2
edid-decode -S --cvt w=5120,h=2160,fps=60,rb=2
edid-decode -S --cvt w=5120,h=2880,fps=60,rb=2
edid-decode -S --cvt w=6016,h=3384,fps=60,rb=2
edid-decode -S --cvt w=5120,h=2160,fps=120,rb=2
edid-decode -S --cvt w=5120,h=2880,fps=120,rb=2
edid-decode -S --cvt w=7680,h=4320,fps=60,rb=2
edid-decode -S --cvt w=3840,h=2160,fps=240,rb=2
edid-decode -S --cvt w=6016,h=3384,fps=120,rb=2
edid-decode -S --cvt w=10240,h=4320,fps=60,rb=2
edid-decode -S --cvt w=7680,h=4320,fps=120,rb=2
edid-decode -S --cvt w=10240,h=4320,fps=120,rb=2

CVT:  3840x2160   59.999954 Hz  16:9    133.320 kHz    522.614000 MHz (RBv2)
CVT:  5120x2160   60.000000 Hz  64:27   133.320 kHz    693.264000 MHz (RBv2)
CVT:  5120x2880   60.000000 Hz  16:9    177.720 kHz    924.144000 MHz (RBv2)
CVT:  6016x3384   59.999974 Hz  16:9    208.860 kHz   1273.210000 MHz (RBv2)
CVT:  5120x2160  120.000000 Hz  64:27   274.440 kHz   1427.088000 MHz (RBv2)
CVT:  5120x2880  120.000000 Hz  16:9    365.880 kHz   1902.576000 MHz (RBv2)
CVT:  7680x4320   59.999977 Hz  16:9    266.580 kHz   2068.660000 MHz (RBv2)
CVT:  3840x2160  239.999979 Hz  16:9    582.960 kHz   2285.203000 MHz (RBv2)
CVT:  6016x3384  119.999971 Hz  16:9    429.840 kHz   2620.304000 MHz (RBv2)
CVT: 10240x4320   59.999987 Hz  64:27   266.580 kHz   2751.105000 MHz (RBv2)
CVT:  7680x4320  119.999983 Hz  16:9    548.760 kHz   4258.377000 MHz (RBv2)
CVT: 10240x4320  119.999996 Hz  64:27   548.760 kHz   5663.203000 MHz (RBv2)

5K2K120 is more than 6K60 but less than 8K60 and 4K240.
5K120 is also less than 8K60 and 4K240 so it should work unless Apple is imposing some other limit.

Using DSC@8bpp, DisplayPort 1.4 can go up to 3240 MHz (minus some amount for FEC or other overhead).
DSC is usually 12bpp but 4K240 via HBR3 x4 requires 10bpp. This has been achieved on an Apple Silicon Mac.
A Lilu/Whatevergreen patch exists for Intel Macs to change DSC from 12bpp.

How in Hell did you do that?

 

[joevt]

How in Hell did you do that?

edid-decode is a command which is part of v4l-utils
https://www.linuxtv.org/wiki/index.php/V4l-utils

I have a fork at https://github.com/joevt/v4l-utils which I can build and run on my Mac (I only tested the edid-decode command).

 

[2xmos]

MacOS treats the 57" G95NC as two separate monitors if you use Picture By Picture mode.

On my M2 Max MBP 16" I can run:

• Samsung G95NC split 1: 5120x2160 @ 120 Hz w/ HiDPI 3840x1620.
• Samsung G95NC split 2: 2560x2160 @ 120 Hz w/ HiDPI 1920x2160.
  • 120 Hz inexplicably only works if this side is connected via Displayport. HDMI 2.1 is limited to 60 Hz but works fine at 120 Hz if the split is set to 4K + 4K. MacOS doesn't seem to quite know what to do with an oddball 2560x2160 res.
• Samsung G70A 4K 144 Hz: 3840x2160 @ 144 Hz w/ HiDPI up to 3008x1692

All these work at the same time. What does not work is single input 7680x2160, it maxes out at 3840x1080 HiDPI scaling which is so stupid. PbP must be used to get around these limitations.

If the M4 Max does not allow for this, then it's a clear step back in ability. M4 Pro might be less capable, which is very non-obvious when Apple's own display support specs are so incredibly vague.

Having tested, the M4 max fall into the same limitations, even worse like I said HiDPI 3840x1620 isn't available on it!

Also for the DP issue: I noticed that I can only get 120hz through the HDMI 2 port, the 1 and 3rd one doesn't allow me for it

So doing 21:9 and 11:9 with the 21:9 part through HDMI 2 and 11:9 through DP adapter I manage to have 120hz on both, not sure why u can’t seem to have that

On the other side: I had to use betterdisplay for the 11:9 split cause macOS wasn’t offering me HiDPI for it

 

[hajime]

Has the problem been resolved under the fourth beta version of Thaoe? I wonder if it is hardware issue of the M4 series or software issue.