For LG OLED users: Mac mini M4 does not support HiDPI 4k over HDMI 2.1

[schneeland]

I am sorry that my terminology has triggered so many of you.

I think in the PC/Gaming world, people would probably use "downsampling" to describe rendering at a higher resolution than that of the output display (Nvidia also calls it DSR/Dynamic Super Resolution).

But since it's now clear what you are talking about, I ran 8K/60Hz through a bandwidth calculator and it seems, it'll only work on HDMI with v2.1 and Display Stream Compression. So I'm a bit surprised, it even worked for you before on the M1. Still, thanks for the heads up! It'll be interesting to see what Apple does about this.

 

[neuropsychguy]

Any modern "gaming" OLED monitor will provide indefinitely better colours after calibration than any modern Apple display.

And you'll get to enjoy 240 Hz refresh rate, with perfectly smooth animations, legible text during scrolling, and precise mouse movements.

Got some technical reviews comparing the colors of Apple's displays and OLED monitors? I’d love to read through them so I can possibly switch to an OLED monitor.

 

[parameter]

I haven't luckily needed a new monitor in a long time, but am looking for one now. And probably for a new Mini.

Since I've been out of the game for so long, are most people just buying TVs now for monitors, I think it sounds like with say the LG C2 and such?

Is this the way to go versus buying a "computer display"? Sorry if this is a dumb question, just truly curious on the options and recommendations for something with lots of screen real estate and hidpi.

 

[Fishrrman]

jbell wrote in reply 84:
"there's no doubt it's using the full 3840x2160 resolution and scaling 2x, it's not pixelated at all, and there's good anti-aliasing in there as well. So, I don't understand what the problem is?"

In your case, there IS NO "problem".
You're fine.
Enjoy what you have.

(I also have a 27" 4k display running at "looks like 1080p", and it looks very good.

 

[Raspire]

You are running 1x scaling, which looks bad. We want 2x scaling, which is still possible on older Macs.
We want 7680x4320 base resolution, that "looks like" 3840x2160.

If you're not interested in running native 4k @ HiDPI, then you're all set and there is no need to post in this thread.

Yay, looks like my interpretation was correct. I replied earlier on in the thread. 8k scaled down to 4k i.e 2x scaled works for me but only at 30hz, not 60hz which is what my TV can accept. I also can’t play 8k av1 files on YouTube.

Niche problems but problems nonetheless

 

[Raspire]

I own a Samsung QN700B 55in 8K TV that I have been using with a MacBook Pro 16in M2 Max in 4K HiDPI mode for about 18 months now. Recently bought base Mac mini M4. Both work very well, but it helps if the TV is set in both PC (less image manipulation, at least in theory) and Game (VRR, or variable rate refresh) modes.

When set up, System Information > Hardware > Graphics/Displays should look like the enclosed screenshot. Note UI Looks like: 3840 x 2160 @ 60.00Hz line.

To confirm the TV is in the correct mode, press the large middle select button on the remote. It should read 7680x4320 VRR 60Hz Input Signal Plus at top right.

Also, as you suggested, the quality of the HDMI cable is paramount, as it is pushing 48Gbps. I recommend the Belkin 8K HDMI cable that Apple sells. When buying this cable online, be certain it is being sold by the seller itself (i.e. Amazon or Newegg) instead of a random seller that may see the profit in attempting to sell a $2 cable for $40.

Someone made some additional observations on Reddit:

https://www.reddit.com/r/mac/comments/11eym3o

Bummer one can no longer buy a 55in 8K TV in the US.

Ah thanks I haven’t yet tried both pc mode and game mode engaged together. I will it.

 

[waydabber]

Ah thanks I haven’t yet tried both pc mode and game mode engaged together. I will it.

PC mode helps disabling internal chroma subsampling (without PC mode Samsung TVs reduce the horizontal color resolution by half as a longstanding - and rather annoying - tradition for the brand). On the other hand enabling PC mode will generally ruin mini-LED control on the QN700B and QN700C 55" 8K sets. 8K@60Hz should work without PC mode just fine, only Input Signal Plus is required for that - if it does not work, then it might be a cable issue. Game mode is only required for VRR (and a bit reduced lag), which is needed to disable a sharpening feature in PC mode that would otherwise make fonts look funny. Samsung is really trying to do everything to make these TVs difficult to enjoy properly - the 8K panel itself is great but the rest is just plain painful.

 

[Thisismattwade]

jbell wrote in reply 84:
"there's no doubt it's using the full 3840x2160 resolution and scaling 2x, it's not pixelated at all, and there's good anti-aliasing in there as well. So, I don't understand what the problem is?"

In your case, there IS NO "problem".
You're fine.
Enjoy what you have.

(I also have a 27" 4k display running at "looks like 1080p", and it looks very good.

I'm doing this, albeit through the TB3/USB4 port on my base M1 MBA, and agree that it looks great. However, this thread has been very educational for me, especially with some of the links other posters have provided.

DELL S2722QC:
Resolution: 3840 x 2160 (2160p/4K UHD 1 - Ultra High Definition)
UI Looks like: 1920 x 1080 @ 60.00Hz
Mirror: Off
Online: Yes
Rotation: Supported

 

[zapmymac]

Instant purchase of the Better Display app! Works great with my LG 4k Costco monitor, and M2 base Mini…13 months now. Nothing fancy mind you, but it noticeably works just a little bit better and that’s good enough for me an average user.

 

[zapmymac]

I am sorry that my terminology has triggered so many of you.

Here's my MBP M1 Pro connected to LG C2 with flashed USB-C adapter.
View attachment 2451377
An here's the M4 Pro mini:
View attachment 2451372


I want the M4 to do what the M1 does. Whatever you want to call that, I don't care.

The point of the thread is to warn others considering purchasing the mini who want to run this setting.
Apple's specs do not make it clear that the M4 chip cannot do what an M1 can.
I would like to raise awareness and get others to contact Apple about this, so they hopefully fix it.

If you enjoy using "looks like" 1920x1080 or any other resolution, then great. I don't.
Thanks!

Interesting that your two screenshots are noticeable different in quality. The top one is razor sharp, the bottom one is fuzzy…👀👀

good points though ✅✅👌

 

[the future]

I haven't luckily needed a new monitor in a long time, but am looking for one now. And probably for a new Mini.

Since I've been out of the game for so long, are most people just buying TVs now for monitors, I think it sounds like with say the LG C2 and such?

Is this the way to go versus buying a "computer display"? Sorry if this is a dumb question, just truly curious on the options and recommendations for something with lots of screen real estate and hidpi.

Apparently, some people do this, but for normal use I wouldn't recommend it. TVs are just huge compared to regular displays and will overwhelm your vision at regular viewing distances (i.e. on a normal desk). Also, their ppi (pixels per inch) is very low compared to good monitors.

 

[Raspire]

PC mode helps disabling internal chroma subsampling (without PC mode Samsung TVs reduce the horizontal color resolution by half as a longstanding - and rather annoying - tradition for the brand). On the other hand enabling PC mode will generally ruin mini-LED control on the QN700B and QN700C 55" 8K sets. 8K@60Hz should work without PC mode just fine, only Input Signal Plus is required for that - if it does not work, then it might be a cable issue. Game mode is only required for VRR (and a bit reduced lag), which is needed to disable a sharpening feature in PC mode that would otherwise make fonts look funny. Samsung is really trying to do everything to make these TVs difficult to enjoy properly - the 8K panel itself is great but the rest is just plain painful.

Wow I didn’t realise I was speaking with the creator of BetterDisplay, that’s not sarcasm. I just hopped onto GitHub and noticed your username against the BetterDisplay repo.

What does GPU dithering do? Great App btw.

Re my 8k Samsung, been playing with setting this morning and I just can’t get 60hz 8k to show up still just 30hz. It’s my TV, it’s a 2018 Q900R, as I used a Xbox Series X HDMI 2.1 cable today which absolutely should have the required bandwidth. Feel scammed by Samsung, they mis sold it to me by advertising 60hz capabilities, might take it up with trading standards after testing more 8k sources. This was the first time finding out for me

 

[JustStreamingAA]

I don't want to offend anyone or be misunderstood, but what I read in this forum discussion reminded me of the following story. I would like to share it first and then continue.

The Turkish idiom "hoşafın yağı kesildi" (literally, "the oil of the compote has been cut") originates from an event in the Ottoman Empire's Janissary Corps. Traditionally, the cook used the same ladle to serve both oily dishes and compote, resulting in a layer of oil floating on the compote. To improve hygiene, a new regulation mandated separate ladles for each dish, eliminating the oil layer on the compote. However, the Janissaries perceived this change as a deprivation and protested, demanding the return of their "oily compote." Today, this idiom is used to describe situations where people feel dissatisfied when an old but familiar element is removed, even if the change itself is an improvement.

Drawing a parallel to the topic here, it seems to me that some reactions to the changes in display scaling on macOS are similar. Previously, macOS primarily optimized its scaling for Apple-manufactured displays, often rendering third-party 4K and 2K displays at a higher resolution and then downscaling them. This sometimes resulted in inconsistent image quality, especially if the resolution did not match Apple's preferred standards. With the introduction of the M4 processor family and recent software updates, it appears that Apple has started to accommodate a wider range of high-resolution displays with better scaling support. From my perspective, this shift is more of an improvement than a deficiency.

That being said, I want to acknowledge a valid point raised by some users: the perceived quality of the image may not meet their expectations. It's true that on a 4K display, the image quality cannot exceed 4K resolution. However, when static images, particularly those that are not vector-based, are rendered at a higher resolution before being scaled down, they may appear sharper. This can create the illusion of better quality, even if the actual pixel count hasn't increased.

In summary, I believe the changes Apple has made in its approach to scaling are intended to enhance user experience across a wider variety of displays. However, it's understandable that some users might feel that the new behavior does not meet their expectations, especially if they were accustomed to a certain look or feel in previous versions of macOS. It seems to me that the reactions here may stem from a perceived drop in quality. I apologize in advance if I have misunderstood the concerns.

 

[hgfjhbvytjdnb]

EDIT: 4k @120HZ is working with M4/M4 Pro. This thread is about running at a scaled/downsampled "looks like" 3840x2160 resolution, which is not currently supported on M4.

Not sure I gechu.
- You have a 3840x2160 (4K) display. 3840x2160 (4K) is its native resolution (what it can physically display).
- Can you explain why you'd want to run a scaled/downsampled resolution of 3840x2160 (4K) on a display that has a native resolution of 3840x2160 (4K)?
- Can you also explain, how would you even make that work? Since in the "Displays" under settings in macOS, if you have 3840x2160 display (native) the max resolution you can select is 3840x2160 and that is never scaled/downsampled, it's always native. To get scaled you have to drop to any of the resolutions below the native.

I'm confused AF, thanks.

 

[JonathanX64]

Got some technical reviews comparing the colors of Apple's displays and OLED monitors? I’d love to read through them so I can possibly switch to an OLED monitor.

Monitors Unboxed is a decent channel with monitor reviews; it's gaming focused (i.e. they pay too much attention to input lag, pixel response, motion, etc.), but they do review color accuracy as well.

 

[iMac&Cheese]

Does the M28U/M32U support RGB via USB-C at 4k 144hz VRR? While also at a scaled resolution?

Considering it for my M1 Pro

 

[Shin-Ra]

I’m using a base M4 mini with an LG C2 OLED at the default, recommended resolution scaling of 3840x2160 (HiDPI ‘looks like 1920x1080’)

That’s all working fine and my 48Gbps HDMI cable also enables 120Hz and 40-120Hz VRR, and HDR combined with either refresh option.

My no.1 problem is getting full screen video content (mainly YouTube) to synchronise perfectly with display refresh. With VRR enabled, full screen video is distractingly juddery, and the VRR readout (mash green TV remote button) on the TV shows the refresh fluctuating constantly instead of locking steady to the refresh rate of the full screen video.

Locking the Mac to output 120Hz or 60Hz instead of VRR 40-120 results in much less judder in normal 30/60fps content but it’s still not as smooth as the YouTube app on the TV. YouTube stats for nerds (on Mac) reports no dropped frames so decoding isn’t an issue just refresh-matching. Obviously 25/50fps content doesn’t fit into 60/120Hz so either VRR or MacOS switching display refresh on-the-fly is needed for that, the latter I wouldn’t expect outside Apple TV hardware.

There’s a bug with the TV or MacOS not switching out of VRR properly to FIXED 120/60Hz refresh, the tv displays 61Hz VRR steady or 122Hz VRR steady but this can be overcome by restarting the TV.

Other things I’ve observed are MacOS in VRR dropping to 40Hz when there’s nothing animating, similar to iOS/iPad OS energy saving, this isn’t so great on current generation OLED because brightness can fluctuate (minor flicker), especially in darker content with VRR swings. Something as little as the playback controls and mouse cursor appearing in full screen video also swings VRR up to max ~120Hz so I’m only observing video smoothness when video is full screen without any UI showing.

These 24/60fps test videos are useful for comparing options but additional judder (especially in VRR) is observable in any content compared to the tv’s own YouTube app which has direct control over TV refresh, the ideal scenario.

If anyone can recommend a better thread for VRR and refresh-related issues I’d be happy to have the discussion over.

 

[DanneP]

I still don't get what 4K HiDPI is and when this limitation is a problem.

As far as I understand 3840 x 2160 with 200 % scaling (elements the same size as if you had 1080p) is ok (?).

But if you want it to look like 1620p the M4 won't cut it since the image will be rendered as 3240p (and resized to 2160p) and 3240p is too large for the framebuffer of the M4?

 

[Chancha]

I still don't get what 4K HiDPI is and when this limitation is a problem.

As far as I understand 3840 x 2160 with 200 % scaling (elements the same size as if you had 1080p) is ok (?).

But if you want it to look like 1620p the M4 won't cut it since the image will be rendered as 3240p (and resized to 2160p) and 3240p is too large for the framebuffer of the M4?

On M1 M2 M3 the limit was 6144 px, after using it as a 2x virtual buffer, the max scaled down width is 3072 px. The M4 is supposed to have lifted that, as evident by the Dell 5k2k HiDPI with scaling higher than that working for some users.

With your example, the screen is rendered at 3840 wide, well below the limit so no issues.

 

[DanneP]

On M1 M2 M3 the limit was 6144 px, after using it as a 2x virtual buffer, the max scaled down width is 3072 px. The M4 is supposed to have lifted that, as evident by the Dell 5k2k HiDPI with scaling higher than that working for some users.

With your example, the screen is rendered at 3840 wide, well below the limit so no issues.

Thanks for your input! Ok, so it's limited by width and not by height.

But when is it a problem then? What can M<4 do that M4 cant?

 

[eltoslightfoot]

Nobody knows at this point? I don’t have mine yet so I can’t test anything.

 

[SolidGold]

I can confirm that I have the same problem - no HiDPI@4k resolution - with my 16" M3Max Maxbook Pro Top Spec 128GB RAM and my LG42C3 - OLED 4k 42" 120Hz - tested using HDMI 2.1 8K certified cable.
On side note, I use a LG Monitor as well, model 32GQ950-B - LCD 4k 32" 160Hz - tested with a USB-C to DisplayPort cable both directly connected and through and OWC Thunderbolt 4 Hub, this wasn't working with HiDPI@4k until I connected the LG42C3 Tv and used Better Display to change the resolution and enable the HiDPI.
I would be pleased to hear someone else with same/similar setup as me

 

[DanneP]

I can confirm that I have the same problem - no HiDPI@4k resolution - with my 16" M3Max Maxbook Pro Top Spec 128GB RAM and my LG42C3 - OLED 4k 42" 120Hz - tested using HDMI 2.1 8K certified cable.
On side note, I use a LG Monitor as well, model 32GQ950-B - LCD 4k 32" 160Hz - tested with a USB-C to DisplayPort cable both directly connected and through and OWC Thunderbolt 4 Hub, this wasn't working with HiDPI@4k until I connected the LG42C3 Tv and used Better Display to change the resolution and enable the HiDPI.
I would be pleased to hear someone else with same/similar setup as me

HiDPI@4k is 7680x4320 downsized to 3840x2160?

 

[SolidGold]

HiDPI@4k is 7680x4320 downsized to 3840x2160?

Yes, I confirm HiDPI@4k I mean 7680x4320 downsized to 3840x2160.
You can check the attached screenshot, that's the highest HiDPI resolutions I can get with my equipment.

 

[kasakka]

Previously, macOS primarily optimized its scaling for Apple-manufactured displays, often rendering third-party 4K and 2K displays at a higher resolution and then downscaling them. This sometimes resulted in inconsistent image quality, especially if the resolution did not match Apple's preferred standards. With the introduction of the M4 processor family and recent software updates, it appears that Apple has started to accommodate a wider range of high-resolution displays with better scaling support. From my perspective, this shift is more of an improvement than a deficiency.

That being said, I want to acknowledge a valid point raised by some users: the perceived quality of the image may not meet their expectations. It's true that on a 4K display, the image quality cannot exceed 4K resolution. However, when static images, particularly those that are not vector-based, are rendered at a higher resolution before being scaled down, they may appear sharper. This can create the illusion of better quality, even if the actual pixel count hasn't increased.

In summary, I believe the changes Apple has made in its approach to scaling are intended to enhance user experience across a wider variety of displays. However, it's understandable that some users might feel that the new behavior does not meet their expectations, especially if they were accustomed to a certain look or feel in previous versions of macOS. It seems to me that the reactions here may stem from a perceived drop in quality. I apologize in advance if I have misunderstood the concerns.

I disagree.

Apple has done seemingly nothing to improve their system, instead they have just introduced regressions where 5Kx2K displays are not getting the right scaling levels, 4K displays can't do native res HiDPI etc.

Meanwhile the very extreme - my 8Kx2K superultrawide, is according to reports still not capable of above 3840x1080 HiDPI on M4 Max. Yet the system can run up to 3 4K+ displays each with separate HiDPI scaling. Even on my M2 Max I'm literally running this:

• Samsung G95NC left side as a 5Kx2K @ 120 Hz display. Scaled to 3840x1620 HiDPI. Render res 7680x3240
• Samsung G95NC right side 2560x2160 @ display. Scaled to 1920x2160 HiDPI. Render res 3840x3240
• Samsung G70A running at 4K @ 60 Hz. Scaled to 2560x1440 HiDPI. Render res 5120x2880.

So I'm rendering a whopping 16Kx3K array of displays here, but MacOS is unable to scale the G95NC as one display to 11Kx3K. Meanwhile Windows 11 can do this with a low tier, several years old GPU.

If I run my G95NC as two 4K displays, I see far less issues on MacOS. With my 21:9 + 11:9 split it's regular that MacOS will detect one of the sides incorrectly as e.g 3440x1440, or the 2560x2160 as a non-HiDPI. I have to use BetterDisplay to reinitialize the displays after waking from sleep, but it does not happen every time.

So I believe Apple is literally doing some hacks behind the scenes for common resolutions like 4K and everything outside that falls into a weird will-it-won't-it-work limbo. Apple should not be doing anything to deal with specific resolutions. You'd think a generic system would be able to handle any display, up to any resolution and aspect ratio that is supported.

Similarly native res HiDPI options wouldn't even be a question if Apple's scaling system wasn't so underwhelming that everything just looks like crap without HiDPI scaling.