How to change the actual screen resolution in macOS?

[tony359]

I've realised that changing the "resolution" in Displays, won't change the actual resolution sent to the monitor, it just rescales everything to make it look like the selected resolution. I'm talking about HDMI monitors on a mac mini.

Sometimes this is a nice feature. But there are times where I want the mac to send a lower resolution stream to the monitor for XYZ reasons.

I haven't been able to find how to do that. My monitor is constantly reporting its native resolution and nothing I do changes that.

I've read about changing EDID and stuff like that - surely there is a simpler way to tell macOS "send FullHD even though the monitor is reporting 4K capable"??

Thanks!

 

[blufrog]

AFAIK, this is by design. The OS knows to render the full screen, and everything is just scaled to fit. Seeing as GPUs are so fast now, there is no reason to not scale the UI to the screen. The reason they do this is to have a consistent UI size, regardless of physical display size/resolution. i.e., icons drawn on my 40" 4K display have the same size as the icons on my 27" iMac 5K, despite the displays having radically different pixel densities, dimensions, and resolutions.

 

[blufrog]

Just looking here, the best you can do is select the option for "Most Space" in Displays. This will draw the UI 1:1 with your physical screen resolution (in my case it says 3840x2160 as I have a 4K monitor).

 

[QuarterSwede]

Betterdisplay is your friend.

 

[tony359]

I understand why macOS might want to do that but there are situations where I might need a lower actual resolution: for example, my hdmi cable is not great and I’m getting artefacts in 4K (of course the solution is to replace the cable but it’s an example)


@QuarterSwede
I have better display and I fiddled with it with no luck. Can you give me a pointer please?

 

[galad]

Click on the Advanced button and check "Show resolution as list", the click on the "Show all resolutions".

 

[tony359]

Click on the Advanced button and check "Show resolution as list", the click on the "Show all resolutions".

Thanks - That doesn't change the output resolution though - I confirmed on the monitor's own menu. It's a 4K monitor, it always get 4K regardless of what I select.

My understanding is that those resolutions mean "I will keep driving the monitor at the native resolution but I will make it look like whatever you select".

Which is great for many use case scenarios. But I'd like to be able to select a lower ACTUAL resolution if I needed to.

 

[galad]

Looks like on Apple Silicon it always rescale to the display actual resolution. LCD and OLED panels have a fixed resolution anyway, so in the end it won't make much difference. I guess the only option is to play around in Better Display.

 

[tony359]

I have BetterDisplays but I couldn't find a way to change the actual output. I'd agree you wouldn't normally want to send a non-native output to your screen, it's just sometimes it might be required in a temporary situation.

 

[joevt]

Does SwitchResX or BetterDisplay let you create custom timings on Apple Silicon? They should show which modes are scaled modes and which modes are actual timings. I know SwitchResX does on Intel Macs.

 

[tony359]

No, unless all those options live under the "Enable flexible scaling" umbrella?

 

[maflynn]

Another vote for Better display.

This is where both Windows and Linux offer a superior experience to that of Apple. My 4k monitor looks better, and I have better scaling choices in those operating systems then on macos.

 

[Fishrrman]

And yet one more vote for BetterDisplay.

If you can't get your display "the way you want it" with BetterDisplay...
then
You ain't gettin' it.

Hmmm...
Maybe I missed it above, but...
- tell us WHAT MAC you have
- tell us WHAT DISPLAY you have
- tell us WHAT RESOLUTION you want to see.

 

[QuarterSwede]

Potentially this solution. Also, BetterDisplay and SwitchResX can load custom EDIDs so you can report any resolution you want to macOS. Be careful, that’s a good way to create a non working output.

I’m not sure an LCD will output anything other than native. It’s fixed. And even if it says it is doing so the monitor would be scaling the output anyway.

 

[generdude]

I know nothing about displays but I have a display for my mac mini that connects via USB-C which I was told is better than HDMI.

 

[bogdanw]

I've realised that changing the "resolution" in Displays, won't change the actual resolution sent to the monitor, it just rescales everything to make it look like the selected resolution. I'm talking about HDMI monitors on a mac mini.

If you check “Show all resolutions”, you should see 1920 x 1080 (low resolution). That should be the setting for true FullHD output.

 

[tony359]

If you check “Show all resolutions”, you should see 1920 x 1080 (low resolution). That should be the setting for true FullHD output.
View attachment 2630285

It does not unfortunately. At least on my display. The scaling changes and gets worse but not the output. The monitor still receives 4K.

I’m not sure an LCD will output anything other than native. It’s fixed. And even if it says it is doing so the monitor would be scaling the output anyway.

Of course they do! They will re-scale it internally of course. But a good LCD monitor can accept any resolution.

The potential solution you linked (thanks!) doesn't seem to be working with later Apple silicon machines...


Once again, I understand nobody wants to run their LCD display at a resolution different than the native one. But when you have to deal with many different systems, monitors, projectors, splitters, cables, there will be THAT occasion where things just don't automagically work and you need a different resolution.

With Windows, I can set whatever I want as long as it's a supported one. With macOS it doesn't seem so and I find it very limiting.

No, changing EDID on someone else's monitor doesn't sound like a viable option 🙂

 

[QuarterSwede]

I know nothing about displays but I have a display for my mac mini that connects via USB-C which I was told is better than HDMI.

Correct. That would be DisplayPort (spec depends on the chip you have) which can be higher bandwidth than HDMI 2.1 (the latest).

 

[QuarterSwede]

Have you tried turning off HiDPI mode in BetterDisplay?

macOS hides this mode because it’s considered a worse output for most people.

I can make my monitor (4K) look borderline unreadable or terrible with that off.

 

[QuarterSwede]

The potential solution you linked (thanks!) doesn't seem to be working with later Apple silicon machines...

View attachment 2630289

He is recommending editing the Eizo’s EDID to change the timing (you can back it up). BetterDisplay will output what you tell it (when you’re essentially hacking it), so if you’re confident the Eizo will display a 1080p signal (non-macOS scaled signal) then check out how to do so. This is beyond my knowledge so I can’t guide you. Good luck!

 

[tony359]

Have you tried turning off HiDPI mode in BetterDisplay?
I can make my monitor (4K) look borderline unreadable or terrible with that off.

Yes, same here.
But the monitor still receives a 4K signal. 🙂

Changing EDID on a monitor to fool the OS to output a non-native resolution is not an option I'm afraid.