Mac mini 2018 bad UI-performance with LG 5K-Display

[ikaka]

Your math is off the chart.

that's what the MacBook Pro's vmem reports used hooked up to the same displays, with the lid closed hovers around 3.5GB. Also with just 1 4k displays it swaps a lot less and performed much smoother. So I do believe it's the memory issue.

[doublepost=1542137444][/doublepost]In bootcamp, with one display
iGPU tries to grab 4GB out of 8GB available

 

[Spectrum]

I have 2x 4k monitors hooked up to the i7 mini with 8gb and I also see it stuttering significantly, but I believe the issue is in memory, since it needs about 3.5-4GB to run 2 4k displays, therefore the system has only 4gb left for everything else and for MacOS is super low and then the video memory starts swapping and boom. I have 32GB coming this week, hope it fixes it.

What resolution do you have them set at?

 

[macdos]

that's what the MacBook Pro's vmem reports used hooked up to the same displays, with the lid closed hovers around 3.5GB. Also with just 1 4k displays it swaps a lot less and performed much smoother. So I do believe it's the memory issue.

[doublepost=1542137444][/doublepost]In bootcamp, with one display
iGPU tries to grab 4GB out of 8GB available

To *drive* a 4K screen you need 3480x2160x60 = 430 MB.

Apple recommends at least 1 GB to edit 4K movies in FCP, to put it all in perspective.

 

[Spectrum]

To *drive* a 4K screen you need 3480x2160x60 = 430 MB.

Just interested...the x60 means each pixel requires 60 bytes to spec its colour? That seems huge. Even 10 bit colour in three channels should only be 30 bits = just under 4 bytes.

 

[ikaka]

To *drive* a 4K screen you need 3480x2160x60 = 430 MB.

Apple recommends at least 1 GB to edit 4K movies in FCP, to put it all in perspective.

Yes, but I'm going by actual day today usage, having apps open, that .9gb/3.9 in windows was just booted up nothing else open, so it does eat more. I have them at 3008x1692 (the middle Scaled option). When I have two monitors plugged in and just safari open in MacOS I immediately see swapping and then stuttering. It's more or less usable with 1 display.

 

[Spectrum]

Yes, but I'm going by actual day today usage, having apps open, that .9gb/3.9 in windows was just booted up nothing else open, so it does eat more. I have them at 3008x1692 (the middle Scaled option). When I have two monitors plugged in and just safari open in MacOS I immediately see swapping and then stuttering. It's more or less usable with 1 display.

Running at 3008x1692 is much more demanding on the GPU than even 5K.
The way the scaling works, it will actually be rendering at 6016x3384 on each display, before downsampling to the 4K display. Times two for both displays. What you are asking would be tough even for many dedicated GPUs.

Try setting them at 2560x1440 or 1920x1080 and see if the performance improves (but the size may be too large, but it tests at least GPU power).

 

[ikaka]

Running at 3008x1692 is much more demanding on the GPU than even 5K.
The way the scaling works, it will actually be rendering at 6016x3384 on each display, before downsampling to the 4K display. Times two for both displays. What you are asking would be tough even for many dedicated GPUs.

Try setting them at 2560x1440 or 1920x1080 and see if the performance improves (but the size may be too large, but it tests at least GPU power).

The smoothest is at the native 4k, but it does start swapping immediately.
The screen shot is 4k native then switching to 3008x1692.
2560x1440 runs at about 50-60% GPU usage.

 

[Stephen.R]

In bootcamp, with one display

macOS limits integrated GPU's to 1.5GB max.

 

[Spectrum]

The smoothest is at the native 4k, but it does start swapping immediately.
The screen shot is 4k native then switching to 3008x1692.
2560x1440 runs at about 50-60% GPU usage.

That's really helpful ikaka. Is that with just one 4K screen attached?
Also, when you say 4K native, do you mean with really tiny fonts? Or in the "Looks like 1920x1080; (best for display)" setting? If not, what happens when you switch to the the 'looks like 1920 setting'?

What you are seeing is not great...but then again, you are technically asking the UI to be powering two 6K screens (40 MPixels), and then scale them to 2x4K output (16 Mpixels). That is quite a lot of computation for *any* GPU, let alone an integrated Intel unit.

I know that on my 21 inch 4K iMac, if I select 3008x1692 setting (or something similar), which renders at 6016x3384 then scales to the native 4096x2304 screen, the UI becomes a little bit choppy, and this is only a single screen and also with a slightly more powerful Intel Iris Pro GPU.

 

[Stephen.R]

but it does start swapping immediately

What else is running?

System Information > Graphics will show you how much memory is allocated to the iGPU.

 

[Spectrum]

Yes it is always 1440 default, multiplies evenly. If you try adjusting the scaling further from that, it slows down performance.

I'm not sure if the integer scaling (or not) is relevant, or if it is just the total size of the virtual frame buffer (before scaling).

e.g. If you select "looks like 2560x1440, the max frame rendered is 5120x2880, then scaled 2x.
Whereas if you select higher res: "looks like 3008x1692, the frame buffer will be 6016x3384, then scaled. I think it could be the larger size of the virtual frame rendering that makes performance suffer not necessarily the non-integer scaling.

 

[Synchro3]

To *drive* a 4K screen you need 3480x2160x60 = 430 MB.

Apple recommends at least 1 GB to edit 4K movies in FCP, to put it all in perspective.

1.5 GB needed for a 4K screen (looks like 1440, 10 Bit):

 

[macdos]

1.5 GB needed for a 4K screen (looks like 1440, 10 Bit):

View attachment 804012

That is the maximum VRAM allowed by UHD 630. It looks the same regardless of what monitor you attach. I have 2 x 4K. You can have 3 if you want. Do you think those specs are random?

 

[Tigerman82]

I've been following this thread as I plan on connecting an LG 27UK850 (4K) to the i5 Mac Mini (2018). I don't plan on upgrading the 8 gigs of RAM, at least not right away. Will I have issues? It just seems strange to me that the 2018 Mac Mini couldn't drive these display even with 8 gigs of RAM when those 27" 5K iMacs come with 8 gigs of RAM and supposedly no issues.

 

[T-Bob]

I'm not sure if the integer scaling (or not) is relevant, or if it is just the total size of the virtual frame buffer (before scaling).

e.g. If you select "looks like 2560x1440, the max frame rendered is 5120x2880, then scaled 2x.
Whereas if you select higher res: "looks like 3008x1692, the frame buffer will be 6016x3384, then scaled. I think it could be the larger size of the virtual frame rendering that makes performance suffer not necessarily the non-integer scaling.

Yes I was thinking more of why that is an ideal scaled resolution on 5k, it's not as ideal in other situations where you need to use uneven steps like 150 or 175 on 4k at 27" to get a usable screen.

 

[ncrypt]

I received my i5/8GB last night. Connected to a 4k monitor (LG-27UD68), scaled to 2560 x 1440.

GPU history graph shows around 50% utilisation if you're scrolling / manipulating the UI.

Most of the UI is buttery smooth, including when jumping into Mission Control. If you're switching between spaces or maximising a YouTube video it can drop a few frames, but my usage of those things are pretty infrequent.

Photos app doesn't show any lag, even when scrolling a 80k+ library, or even when maximising / editing a photo, which is impressive.

Let me know if there any other kinds of things you'd like me to check out and I'll try and get around to them tonight

 

[ikaka]

That's really helpful ikaka. Is that with just one 4K screen attached?
Also, when you say 4K native, do you mean with really tiny fonts? Or in the "Looks like 1920x1080; (best for display)" setting? If not, what happens when you switch to the the 'looks like 1920 setting'?

That was both at the native 3840x2160, which is pretty solid.
1920x1080 was hovering at a little above the native resolution.

What you are seeing is not great...but then again, you are technically asking the UI to be powering two 6K screens (40 MPixels), and then scale them to 2x4K output (16 Mpixels). That is quite a lot of computation for *any* GPU, let alone an integrated Intel unit.

Agreed, I actually got pretty good performance with running one at 3840x2160 and the other at 3008x1692
A bit of a compromise

I know that on my 21 inch 4K iMac, if I select 3008x1692 setting (or something similar), which renders at 6016x3384 then scales to the native 4096x2304 screen, the UI becomes a little bit choppy, and this is only a single screen and also with a slightly more powerful Intel Iris Pro GPU.

Yea, I have an RTX 2080 eGPU, just hope they release the drivers at some point.
Gaming in bootcamp with eGPU is fantastic.
[doublepost=1542207184][/doublepost]

I've been following this thread as I plan on connecting an LG 27UK850 (4K) to the i5 Mac Mini (2018). I don't plan on upgrading the 8 gigs of RAM, at least not right away. Will I have issues? It just seems strange to me that the 2018 Mac Mini couldn't drive these display even with 8 gigs of RAM when those 27" 5K iMacs come with 8 gigs of RAM and supposedly no issues.

I've been using an i7 with 8GB for a few days. You do take a performance hit when it's swapping and OSX is super memory hungry as it tries to cache everything. If you intent on doing anything more than email/web browsing I'd recommend upgrading the memory.

 

[n-evo]

If you used a scaled resolution the framerate tanks no matter what hardware you have. I've experienced it on multiple Macs, including high end ones.

Every MacBook Pro starting 2016 has scaled resolution turned on by default. I never noticed any stuttering on my 2017 MacBook Pro. Kinda weird it's that bad on an external screen.

 

[strawbale]

I received my i5/8GB last night. Connected to a 4k monitor (LG-27UD68), scaled to 2560 x 1440.

GPU history graph shows around 50% utilisation if you're scrolling / manipulating the UI.

Most of the UI is buttery smooth, including when jumping into Mission Control. If you're switching between spaces or maximising a YouTube video it can drop a few frames, but my usage of those things are pretty infrequent.

Photos app doesn't show any lag, even when scrolling a 80k+ library, or even when maximising / editing a photo, which is impressive.

Let me know if there any other kinds of things you'd like me to check out and I'll try and get around to them tonight

How is the crispness of text compared to set at 1920*1080 or 3840*2160 ?

 

[Spectrum]

I received my i5/8GB last night. Connected to a 4k monitor (LG-27UD68), scaled to 2560 x 1440.Let me know if there any other kinds of things you'd like me to check out and I'll try and get around to them tonight

Like ikaka, please can you try some other scalings like 2880x1620, 3008x1692 or 3200x1800?
These should get progressively more demanding. Native (3840x2160) should then be easier again for the GPU even though the fonts are tiny.

Every MacBook Pro starting 2016 has scaled resolution turned on by default. I never noticed any stuttering on my 2017 MacBook Pro. Kinda weird it's that bad on an external screen.

The Macboook pro has a lower native screen resolution (2560x1800). For the default scaling "looks like 1440x1050", only requires rendering at 2880x2100 (6 Mpixel), then scaling down to 2560x1800. What ikaka is asking is about 4x as computationally intensive (rendering at 6016x3384 then scaling to 3840x2160). Then do that twice - for TWO screens!

Your 2017 MBPro also has a dedicated GPU doesn't it?
[doublepost=1542209376][/doublepost]

Agreed, I actually got pretty good performance with running one at 3840x2160 and the other at 3008x1692
A bit of a compromise

What about if you use "non-retina" 1x scaling and just ask the display to run at non-retina (1x) 3008x1692, scaled UP to 3840x2160 (rather than retina (2x) 6016x3384 scaled DOWN to 3840x2160)?

This is scaling prior to retina display tech launched. With a high DPI display it might not look too bad, and is 4x less computation for the GPU.

How big are your screen diagonals? 3840x2160 native must make things pretty tiny...

 

[ncrypt]

How is the crispness of text compared to set at 1920*1080 or 3840*2160 ?

Not as bad as some make out IMO. I find it crisper than non retina -i.e. 1080p or 1440p, but not quite as a good as a 4K or 5K display at a native (3840x2160) or native scaled (2560x1440@2x) resolution.

 

[ikaka]

Like ikaka, please can you try some other scalings like 2880x1620, 3008x1692 or 3200x1800?
These should get progressively more demanding. Native (3840x2160) should then be easier again for the GPU even though the fonts are tiny.


The Macboook pro has a lower native screen resolution (2560x1800). For the default scaling "looks like 1440x1050", only requires rendering at 2880x2100 (6 Mpixel), then scaling down to 2560x1800. What ikaka is asking is about 4x as computationally intensive (rendering at 6016x3384 then scaling to 3840x2160). Then do that twice - for TWO screens!

Your 2017 MBPro also has a dedicated GPU doesn't it?
[doublepost=1542209376][/doublepost]

What about if you use "non-retina" 1x scaling and just ask the display to run at non-retina (1x) 3008x1692, scaled UP to 3840x2160 (rather than retina (2x) 6016x3384 scaled DOWN to 3840x2160)?

This is scaling prior to retina display tech launched. With a high DPI display it might not look too bad, and is 4x less computation for the GPU.

How big are your screen diagonals? 3840x2160 native must make things pretty tiny...

I DEMAND 4x! work you POS! lol
I have 2x U2718Q 27"
4k native is tiny...

 

[Spectrum]

I DEMAND 4x! work you POS! lol
I have 2x U2718Q 27"
4k native is tiny...

Haha! Try non-retina scaling...just for fun. It might be OK at that DPI...you never know...

 

[ncrypt]

Like ikaka, please can you try some other scalings like 2880x1620, 3008x1692 or 3200x1800?
These should get progressively more demanding. Native (3840x2160) should then be easier again for the GPU even though the fonts are tiny.

• Choppiness switching spaces still exists on all other scaled resolutions. Smooth at native res.
• Photos starts to show some lagginess when opening a photo at 3008x1692 and above. Smooth at native res.
• Full screening YouTube is acceptable at 1920x1080, choppy at other scaled resolutions. Smooth at native.
• Scrolling etc is smooth at all resolutions.

Ultimately, I'm happy with the performance at 2560x1440, everything is smooth other than space switching and full screening YouTube. Anything above that gets quite choppy. Albeit, I don't have a 2880x1620 resolution presented to me to test.

If you're using a display above 32", I would definitely consider running at native 3840x2160, it's great.

 

[Spectrum]

• Choppiness switching spaces still exists on all other scaled resolutions. Smooth at native res.
• Photos starts to show some lagginess when opening a photo at 3008x1692 and above. Smooth at native res.
• Full screening YouTube is acceptable at 1920x1080, choppy at other scaled resolutions. Smooth at native.
• Scrolling etc is smooth at all resolutions.

Ultimately, I'm happy with the performance at 2560x1440, everything is smooth other than space switching and full screening YouTube. Anything above that gets quite choppy. Albeit, I don't have a 2880x1620 resolution presented to me to test.

If you're using a display above 32", I would definitely consider running at native 3840x2160, it's great.

Thanks for the details crypt. Even at 32 inch the native res must make things pretty small, no? I was working it out and to get equivalent DPI to a regular 27 inch 2560x1440, would need a 40.5 inch display!

But I guess 3840x at 32 inch is probably similar to ikaka running scaled 3006x at 27 inch.

EDIT: Actually, I just realised the 3840x2160 on a 32 inch is the same as 2560x1440 on a retina 21 inch iMac. And I quite often use that option! I need to be close to the screen though...