Will Apple Silicon solve the 1440p scaling issue?

[dingclancy23]

Hi all,

I am in the market for a new monitor and I am considering a 27inch 4k monitor. However, my research shows how OSX essentially blows up the resolution then shrinks to fit to a 1440p HIDPI resolution. I am working from a nTB Macbook Pro 2017, but I have read this being an issue on stronger MBPs and Mac Minis.

Going back down to a non-retina 1440p might be the best solution at the moment. I am just wondering if I just buy the 4k monitor in preparation for ARM Macs. Would having an ARM Mac solve the scaling lag issue on odd-scaled resolutions?

It also looks like Apple will be releasing 24inch Macs which will be too big UI for a retina 1080-style resolution. It makes sense that they will be releasing 4k 24inch Macs that is scaled at 1440p, which is exactly the monitor setup I need.

Thanks for your help!

 

[Erehy Dobon]

ASi isn't a resolution panacea.

Apple graphics subsystems have supported 1080p, 1440p, 2160p for years.

I have a Mac mini 2018 that is driving a 1440p monitor at native resolution. There's also a Windows PC plugged into a different monitor input. Their screen graphics quality are comparable.

 

[aednichols]

I have been using a 2016 15” MBP with the base GPU for years with a 4K @ 1440p and it is absolutely fine.

I would be concerned about Intel graphics though, especially anything before Ice Lake (2020 13” MBP).

 

[Erehy Dobon]

As we approach the ASi launch I see that MacRumors readers are increasingly subjected to completely unrealistic "scenarios."

 

[dingclancy23]

I have been using a 2016 15” MBP with the base GPU for years with a 4K @ 1440p and it is absolutely fine.

I would be concerned about Intel graphics though, especially anything before Ice Lake (2020 13” MBP).

Yes that is where I am at (nonTB - integrated graphics). But in any case, I can wait if the new ARM integrated GPU can solve the scaling issue on their base ARM Macbook Air.

 

[aednichols]

Yes that is where I am at (nonTB - integrated graphics). But in any case, I can wait if the new ARM integrated GPU can solve the scaling issue on their base ARM Macbook Air.

Even the current Intel MacBook Air claims to support the 6K Pro Display XDR on paper. How smooth that is in practice is another story.

 

[Erehy Dobon]

A lot of this is the given company's commitment in software.

The upcoming PlayStation 5 game console has great graphics capabilities but won't output 1440p video while the previous Xbox gained this capability a couple of years ago.

PS5 won't support Dolby Vision nor Dolby Atmos either rather relying on Sony's less-recognized homegrown tech.

Obsessing over absolute specs is less important than how well the functional features are implemented.

 

[leman]

Not really sure what you mean by “scaling issue”, been using 4K displays with variety of Mac hardware for years without any problems. HiDPI in macOS works the way it works. If you have a 4K display, it will render to it according to the scaling factor you choose. Apple Silicon won’t change anything here.

 

[aednichols]

Not really sure what you mean by “scaling issue”, been using 4K displays with variety of Mac hardware for years without any problems. HiDPI in macOS works the way it works. If you have a 4K display, it will render to it according to the scaling factor you choose. Apple Silicon won’t change anything here.

In order to display 1440p on a 4K display, the GPU has to render at 5K and then downscale.

5K is a lot more taxing than 4K. Then the scaling stacks on top of that, probably not too bad though.

This has been the case for the entire retina Mac era since 2012 (specific resolutions vary).

 

[joevt]

I am in the market for a new monitor and I am considering a 27inch 4k monitor. However, my research shows how OSX essentially blows up the resolution then shrinks to fit to a 1440p HIDPI resolution. I am working from a nTB Macbook Pro 2017, but I have read this being an issue on stronger MBPs and Mac Minis.

Going back down to a non-retina 1440p might be the best solution at the moment. I am just wondering if I just buy the 4k monitor in preparation for ARM Macs. Would having an ARM Mac solve the scaling lag issue on odd-scaled resolutions?

It also looks like Apple will be releasing 24inch Macs which will be too big UI for a retina 1080-style resolution. It makes sense that they will be releasing 4k 24inch Macs that is scaled at 1440p, which is exactly the monitor setup I need.

Thanks for your help!

You mean macOS draws to a 5120x2880 frame buffer and shrinks it to 4K and calls it "Looks like 2560x1440". What's wrong with that? You get smoother text than if it was drawn at 2560x1440 and scaled up to 4K. In the olden days before Apple released HiDPI to the user, they experimented with fractional scales between 100% and 300%. You can try it out in Mac OS X 10.5 Leopard and 10.6 Snow Leopard https://www.tonymacx86.com/threads/adding-using-hidpi-custom-resolutions.133254/post-2175982 There must be a reason why they settled on scaling 200% down to the output resolution of 4K instead of using a 150% scale factor.

 

[aednichols]

You mean macOS draws to a 5120x2880 frame buffer and shrinks it to 4K and calls it "Looks like 2560x1440". What's wrong with that? You get smoother text than if it was drawn at 2560x1440 and scaled up to 4K. In the olden days before Apple released HiDPI to the user, they experimented with fractional scales between 100% and 300%. You can try it out in Mac OS X 10.5 Leopard and 10.6 Snow Leopard https://www.tonymacx86.com/threads/adding-using-hidpi-custom-resolutions.133254/post-2175982 There must be a reason why they settled on scaling 200% down to the output resolution of 4K instead of using a 150% scale factor.

There's nothing wrong with the concept, but in practice many Mac GPUs struggle to run smoothly in this configuration.

 

[leman]

In order to display 1440p on a 4K display, the GPU has to render at 5K and then downscale.

5K is a lot more taxing than 4K. Then the scaling stacks on top of that, probably not too bad though.

This has been the case for the entire retina Mac era since 2012 (specific resolutions vary).

There not an “issue”, that’s how it’s designed to work. In Apples world that is correct behavior and I very much doubt they are going to reduce their image quality going forward.

Anyway, you might be overestimating the cost. The system only redraws parts of the screen that actually change between frames, so it doesn’t have to do nearly as much work as you think it does. Also, scaling is essentially free on modern hardware.

 

[leman]

There's nothing wrong with the concept, but in practice many Mac GPUs struggle to run smoothly in this configuration.

As I wrote above, there is IMO zero chance that Apple will change their approach, but their GPUs are going to be significantly faster than the current entry level Intel Macs, so they might alleviate your performance concerns.

 

[aednichols]

As I wrote above, there is IMO zero chance that Apple will change their approach, but their GPUs are going to be significantly faster than the current entry level Intel Macs, so they might alleviate your performance concerns.

I agree with you, earlier in the thread I was convincing OP that even current iGPU Intel Macs perform fine with this implementation. ARM Macs should be GPU monsters in comparison.

 

[joevt]

In recent times, you have iOS doing super smooth scaling in apps like Safari with the pinch gesture and reverse pinch gesture.

Safari in macOS has variable scaling using theZoom In and Zoom Out menu options.

However, Apple cannot just reinstate the fractional scale factor feature in macOS (I'm pretty sure it would be just a couple lines of code to do that) since it has been several years since Mac OS X Snow Leopard when developers could test fractional scale factors. They would have to announce the feature, then give a year for developers to test/update their apps. Then they would have to decide if they want to add larger scale bit maps for the greater than 200% scale factors.

If you have an 8K display, then you might consider a scale factor up to 400% or more.

Dell 8K Dual Displayport 1.4 Monitor on macOS Catalina

I remember this being discussed earlier (though I can't quite remember where), and the consensus was that macOS didn't know how to handle an 8K image ...

egpu.io

 

[dingclancy23]

I agree with you, earlier in the thread I was convincing OP that even current iGPU Intel Macs perform fine with this implementation. ARM Macs should be GPU monsters in comparison.

Thanks so much! This has been a help!

 

[leman]

However, Apple cannot just reinstate the fractional scale factor feature in macOS (I'm pretty sure it would be just a couple lines of code to do that) since it has been several years since Mac OS X Snow Leopard when developers could test fractional scale factors.

AFAIK, this was dropped from macOS years ago. They ultimately decided to focus on integer scaling factors and utilize super sampling to emulate fractional scaling. Makes things significantly simpler and solves the same problem n

 

[dingclancy23]

In recent times, you have iOS doing super smooth scaling in apps like Safari with the pinch gesture and reverse pinch gesture.

Safari in macOS has variable scaling using theZoom In and Zoom Out menu options.

However, Apple cannot just reinstate the fractional scale factor feature in macOS (I'm pretty sure it would be just a couple lines of code to do that) since it has been several years since Mac OS X Snow Leopard when developers could test fractional scale factors. They would have to announce the feature, then give a year for developers to test/update their apps. Then they would have to decide if they want to add larger scale bit maps for the greater than 200% scale factors.

If you have an 8K display, then you might consider a scale factor up to 400% or more.

Dell 8K Dual Displayport 1.4 Monitor on macOS Catalina

I remember this being discussed earlier (though I can't quite remember where), and the consensus was that macOS didn't know how to handle an 8K image ...

egpu.io

I think regardless of the implementation, there are reasons why current laptops with integrated Intel graphics and even Macbook Pros struggle with external displays. Driving these monitors can put laptops into a thermal corner. An added challenge is that 5k monitors are expensive and not enough manufacturers are making it, so most people who like working on Mac laptops and still want retina-class monitors go to 4k displays and resort to taxing scaling issues.

For reference: macbook pro 16 inch external monitor macrumors site:forums.macrumors.com

Now it will be interesting if by tomorrow, Apple can make the problem go away because Arm Macs just run faster and quieter even if it takes a performance hit with the odd-scaling.

If the new Macbook Air can drive a 4k display and scale it to 1440p HiDPI without turning the fan on, that will be a big win.

And that is just not a spec discussion but also a functional feature.

 

[joevt]

I agree with you, earlier in the thread I was convincing OP that even current iGPU Intel Macs perform fine with this implementation. ARM Macs should be GPU monsters in comparison.

In Big Sur, Apple has added the ability for iGPU of Kaby Lake and Coffee Lake CPUs to use resolutions up to 5120x2880 (a feature that Linux and Windows have had for awhile). This was necessary to support 5120x1440 single connection wide screen displays. The iGPUs seem to be able to handle that fine. I was working on a patch to try and get higher than 5K (just need to lower the refresh rate to keep within the DisplayPort 1.2 bandwidth limit).

Intel Graphics and 5120x1440 testing in Big Sur

I am looking for confirmation of the following result: I believe Apple has enabled support for displays that are wider than 4096 pixels (at least up to 5120) on some Intel GPUs in Big Sur (Windows and Linux have supported this for awhile). One person reported success with Kaby Lake graphics...

forums.macrumors.com

In Catalina, on my Mac mini 2018, I have no trouble with "Looks like 3008x1692" (6K) scaling down to 4K. And it looks pretty good.

AFAIK, this was dropped from macOS years ago. They ultimately decided to focus on integer scaling factors and utilize super sampling to emulate fractional scaling. Makes things significantly simpler and solves the same problem n

The CoreDisplay code adds normal timings and scaled modes. Then it creates HiDPI modes with a 2 factor for each of those. I believe a patch could change the 2 factor into a 1.5 or 3 or whatever. I haven't tried it yet. I don't think a fractional factor would increase the power required for rendering. In fact, it could remove the need for the final output scaling if the frame buffer was the same size as the output signal.

 

[aednichols]

I think regardless of the implementation, there are reasons why current laptops with integrated Intel graphics and even Macbook Pros struggle with external displays. Driving these monitors can put laptops into a thermal corner. An added challenge is that 5k monitors are expensive and not enough manufacturers are making it, so most people who like working on Mac laptops and still want retina-class monitors go to 4k displays and resort to taxing scaling issues.

For reference: macbook pro 16 inch external monitor macrumors site:forums.macrumors.com

Now it will be interesting if by tomorrow, Apple can make the problem go away because Arm Macs just run faster and quieter even if it takes a performance hit with the odd-scaling.

If the new Macbook Air can drive a 4k display and scale it to 1440p HiDPI without turning the fan on, that will be a big win.

And that is just not a spec discussion but also a functional feature.

If there is an Apple store near you big enough to sell the Mac Pro, I'm sure they would let you plug a MacBook Air into the Pro Display XDR.

There is no substitute for the confidence of firsthand experience.

 

[thingstoponder]

4K is a terrible resolution for 27”. Get a 1440p or 5k.