Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.

elliottcable

macrumors member
Original poster
Apr 7, 2007
41
7
Chicago, IL
Is anybody here with a powerful GPU — either a new Mac Pro / MacPro7,1, or a MacBook with an external eGPU — actually successfully using an 8k display, day-to-day?

I got an amazing deal on a Dell UP3218K, Dell's 8k display. You're supposed to use two DisplayPort 1.4 cables to a single GPU to support 8k@60hz; and I've tried nearly every imaginable combination of GPUs, cables, and ports, and basically no matter what I do, I only see the 8k display a, strangely, *two* 8k displays, in macOS's preferences:
Screen Shot 2020-02-01 at 17.05.24.png

SwitchResX manages to "see" that the display supports 8k, even 8k@60Hz,
Screen Shot 2020-02-01 at 17.05.32.png

Unfortunately, when selected, that doesn't make the second MST "display" disappear, and even at 30Hz — which I should be able to do with a single cable! — the picture is extremely blurry:

IMG_4595.jpeg


I doubt the photo does a very good job of conveying the blurriness — sorry, it's got like 300ppi! I don't think I could photograph it without a nice macro lens, lol. It's extremely obvious in person, though; the text is almost unreadable. )=

Anyway: has anybody had _any_ success with this, in any configuration? If so, what combination of equipment makes this work for you? /=
 

Squuiid

macrumors 68000
Oct 31, 2006
1,854
1,571
Is anybody here with a powerful GPU — either a new Mac Pro / MacPro7,1, or a MacBook with an external eGPU — actually successfully using an 8k display, day-to-day?

I got an amazing deal on a Dell UP3218K, Dell's 8k display. You're supposed to use two DisplayPort 1.4 cables to a single GPU to support 8k@60hz; and I've tried nearly every imaginable combination of GPUs, cables, and ports, and basically no matter what I do, I only see the 8k display a, strangely, *two* 8k displays, in macOS's preferences:
View attachment 891869
SwitchResX manages to "see" that the display supports 8k, even 8k@60Hz, View attachment 891871
Unfortunately, when selected, that doesn't make the second MST "display" disappear, and even at 30Hz — which I should be able to do with a single cable! — the picture is extremely blurry:

View attachment 891872

I doubt the photo does a very good job of conveying the blurriness — sorry, it's got like 300ppi! I don't think I could photograph it without a nice macro lens, lol. It's extremely obvious in person, though; the text is almost unreadable. )=

Anyway: has anybody had _any_ success with this, in any configuration? If so, what combination of equipment makes this work for you? /=
Many of us have been waiting for Apple to support this monitor but currently macOS does not.
Dual Link SST at 8K just doesn’t work in macOS. If you run Bootcamp it runs great at 60Hz.
Your only option is to use one cable and tolerate 30Hz for now, and pray that Apple eventually offer support.

I can only suggest that you file it as a bug with Apple:
 
Last edited:
  • Like
Reactions: DeepIn2U

M3Jedi77

macrumors regular
Jun 30, 2007
122
42
Also hoping to pick this monitor up (since it looks like nobody else is brave enough to make an 8K monitor, there is nothing on the horizon).

I currently use an eGPU with my MBP 16". 2 DP cables run from my Vega 56 --> Dell 5K display, and it works flawlessly (at 5K).

I don't have much to add, but wanted to bump this thread so we could keep trying to find a solution!
 

Squuiid

macrumors 68000
Oct 31, 2006
1,854
1,571
Also hoping to pick this monitor up (since it looks like nobody else is brave enough to make an 8K monitor, there is nothing on the horizon).

I currently use an eGPU with my MBP 16". 2 DP cables run from my Vega 56 --> Dell 5K display, and it works flawlessly (at 5K).

I don't have much to add, but wanted to bump this thread so we could keep trying to find a solution!
Have you filed a bug report?
 

Squuiid

macrumors 68000
Oct 31, 2006
1,854
1,571
Yes. Seems like such a simple fix.... Must be too niche to even pop up on their radar :(
Oh, no. I think this is very much a conscious decision, and aimed at pushing the XDR. This is almost certainly the case.
 

M3Jedi77

macrumors regular
Jun 30, 2007
122
42
Oh, no. I think this is very much a conscious decision, and aimed at pushing the XDR. This is almost certainly the case.

You may be right! How is it even possible that the only display above 5K was created years ago...And nothing is coming this year!? HOW?
 

M3Jedi77

macrumors regular
Jun 30, 2007
122
42
Well I accidentally won an 8K on eBay for super cheap... Tried it out with my MBP 16" + eGPU. Just registers as 2 separate 4K displays in 10.15.3. Guess I will be returning it.
 

Squuiid

macrumors 68000
Oct 31, 2006
1,854
1,571
Well I accidentally won an 8K on eBay for super cheap... Tried it out with my MBP 16" + eGPU. Just registers as 2 separate 4K displays in 10.15.3. Guess I will be returning it.
Or run at 4K for now and wait for Apple to fix. If ever.
You can also use BootCamp and run it at 8K 60Hz.
 

M3Jedi77

macrumors regular
Jun 30, 2007
122
42
Or run at 4K for now and wait for Apple to fix. If ever.
You can also use BootCamp and run it at 8K 60Hz.

I've got an XDR and wanted to compare the 2. I'll just stick with the XDR (though viewing angles on the Dell seem better just by eye).

I would have to run Windows to do 8k 60hz though.... I don't have BootCamp setup.
 

elliottcable

macrumors member
Original poster
Apr 7, 2007
41
7
Chicago, IL
I've got an XDR and wanted to compare the 2. I'll just stick with the XDR (though viewing angles on the Dell seem better just by eye).

I would have to run Windows to do 8k 60hz though.... I don't have BootCamp setup.

I've got an XDR and an 8k side-by-side right now; the 8k is on a switch, and can be driven either from a Windows machine at 8k, or my Mac at 4k. It's not ideal, but I'm hoping and hoping Apple adds 8k MST support soon …
 

Squuiid

macrumors 68000
Oct 31, 2006
1,854
1,571
I've got an XDR and an 8k side-by-side right now; the 8k is on a switch, and can be driven either from a Windows machine at 8k, or my Mac at 4k. It's not ideal, but I'm hoping and hoping Apple adds 8k MST support soon …
Does macOS look ok at 4K on the 8K Dell? I'm coming from a 1600p display, so even 4K would be better in macOS and I use Windows quite a bit so 8K there would be great.
But I have heard that 4K in macOS on the Dell looks somewhat blurry for some reason. Is that true?
 

joevt

Contributor
Jun 21, 2012
6,622
4,062
In macOS, you can use the Dell 8K using single 8K 30Hz or dual 3840x4320 60Hz side by side.

You may need to use SwithResX to add the missing timings that Apple removes from the Dell UP3218K EDID:
7680x4320@29.932Hz 130.742kHz 1030.25MHz h(30 10 160 +) v(3 5 40 -) 16:9 preferred​
7680x4320@24.000Hz 104.855kHz 826.26MHz h(48 32 120 +) v(3 5 41 -) 16:9 preferred​
3840x4320@48.000Hz 212.062kHz 856.73MHz h(48 32 120 +) v(3 10 85 -) 16:9​
3840x4320@60.000Hz 262.079kHz 1058.80MHz h(48 32 120 +) v(3 10 35 -) 16:9​
 
  • Like
Reactions: adib and Squuiid

Squuiid

macrumors 68000
Oct 31, 2006
1,854
1,571
In macOS, you can use the Dell 8K using single 8K 30Hz or dual 3840x4320 60Hz side by side.

You may need to use SwithResX to add the missing timings that Apple removes from the Dell UP3218K EDID:
7680x4320@29.932Hz 130.742kHz 1030.25MHz h(30 10 160 +) v(3 5 40 -) 16:9 preferred​
7680x4320@24.000Hz 104.855kHz 826.26MHz h(48 32 120 +) v(3 5 41 -) 16:9 preferred​
3840x4320@48.000Hz 212.062kHz 856.73MHz h(48 32 120 +) v(3 10 85 -) 16:9​
3840x4320@60.000Hz 262.079kHz 1058.80MHz h(48 32 120 +) v(3 10 35 -) 16:9​
So not possible to just show one 4K image on the screen? That throws that idea out of the window. Can't live with 30Hz.
 

M3Jedi77

macrumors regular
Jun 30, 2007
122
42
In macOS, you can use the Dell 8K using single 8K 30Hz or dual 3840x4320 60Hz side by side.

You may need to use SwithResX to add the missing timings that Apple removes from the Dell UP3218K EDID:
7680x4320@29.932Hz 130.742kHz 1030.25MHz h(30 10 160 +) v(3 5 40 -) 16:9 preferred​
7680x4320@24.000Hz 104.855kHz 826.26MHz h(48 32 120 +) v(3 5 41 -) 16:9 preferred​
3840x4320@48.000Hz 212.062kHz 856.73MHz h(48 32 120 +) v(3 10 85 -) 16:9​
3840x4320@60.000Hz 262.079kHz 1058.80MHz h(48 32 120 +) v(3 10 35 -) 16:9​

This is interesting. I wonder if 30hz would be enough for me. I don't play games or anything like that...

So not possible to just show one 4K image on the screen? That throws that idea out of the window. Can't live with 30Hz.

It works great as a 4K monitor (albeit expensive).
 
  • Like
Reactions: Squuiid

elliottcable

macrumors member
Original poster
Apr 7, 2007
41
7
Chicago, IL
In macOS, you can use the Dell 8K using single 8K 30Hz or dual 3840x4320 60Hz side by side.

You may need to use SwithResX to add the missing timings that Apple removes from the Dell UP3218K EDID:
7680x4320@29.932Hz 130.742kHz 1030.25MHz h(30 10 160 +) v(3 5 40 -) 16:9 preferred​
7680x4320@24.000Hz 104.855kHz 826.26MHz h(48 32 120 +) v(3 5 41 -) 16:9 preferred​
3840x4320@48.000Hz 212.062kHz 856.73MHz h(48 32 120 +) v(3 10 85 -) 16:9​
3840x4320@60.000Hz 262.079kHz 1058.80MHz h(48 32 120 +) v(3 10 35 -) 16:9​

It's unclear how to add this in SwitchResX; according to your post on TonyMacX86, though, it looks like I'd just have to remove the override?

(Removed bit about being unable to modify, even with SIP disabled — sudo mount -uw / && killall Finder did the trick.)

Okay, with the DisplayProductID-4147 EDID removed from Displays/Contents/Resources/Overrides/, upon reboot, the UP3218K quickly cycles on and off, without ever showing an image other than black, until the cables are unplugged. Hrm. No dice.

At this point, I'd love to even just get 8k@30Hz! )=
 
Last edited:

Pressure

macrumors 603
May 30, 2006
5,025
1,369
Denmark
It's unclear how to add this in SwitchResX; according to your post on TonyMacX86, though, it looks like I'd just have to remove the override?

(Removed bit about being unable to modify, even with SIP disabled — sudo mount -uw / && killall Finder did the trick.)

Okay, with the DisplayProductID-4147 EDID removed from Displays/Contents/Resources/Overrides/, upon reboot, the UP3218K quickly cycles on and off, without ever showing an image other than black, until the cables are unplugged. Hrm. No dice.

At this point, I'd love to even just get 8k@30Hz! )=

Weird, just removing the DisplayProductID-4147 enabled me to run 8K@30Hz. No need for SwitchResX.
 

joevt

Contributor
Jun 21, 2012
6,622
4,062
It's unclear how to add this in SwitchResX; according to your post on TonyMacX86, though, it looks like I'd just have to remove the override?

(Removed bit about being unable to modify, even with SIP disabled — sudo mount -uw / && killall Finder did the trick.)

Okay, with the DisplayProductID-4147 EDID removed from Displays/Contents/Resources/Overrides/, upon reboot, the UP3218K quickly cycles on and off, without ever showing an image other than black, until the cables are unplugged. Hrm. No dice.

At this point, I'd love to even just get 8k@30Hz! )=
I think removing the override should be sufficient but that leaves the tile info.

The SwitchResX override has file name containing DisplayYearManufacture and DisplayWeekManufacture. Make sure that is removed too?

Connect only one cable?

If you keep the Apple override, you can still use SwitchResX to add the missing timings (add them as Custom Resolutions - the three numbers in parenthesis are Front porch, Sync width, Back porch). SwitchResX creates an override to Apple's override using the DisplayYearManufacture and DisplayWeekManufacture naming convention.
 

elliottcable

macrumors member
Original poster
Apr 7, 2007
41
7
Chicago, IL
Weird, just removing the DisplayProductID-4147 enabled me to run 8K@30Hz. No need for SwitchResX.

Hm. And it's full-res? I can *select* 8K@30Hz in SwitchResX, but it doesn't appear in System Preferences; and when selected, it's clearly not actually rendering at 8k — text is nearly unreadable (although, I mean, it's 8k, so I have to lean in pretty close to tell, nonetheless …)

I think removing the override should be sufficient but that leaves the tile info.

The SwitchResX override has file name containing DisplayYearManufacture and DisplayWeekManufacture. Make sure that is removed too?

Connect only one cable?

If you keep the Apple override, you can still use SwitchResX to add the missing timings (add them as Custom Resolutions - the three numbers in parenthesis are Front porch, Sync width, Back porch). SwitchResX creates an override to Apple's override using the DisplayYearManufacture and DisplayWeekManufacture naming convention.

Yeah, only one cable.

Okay, now I'm wondering if there's something *else* wrong with this display? I've added those timings in SwitchResX …

Screen Shot 2020-03-25 at 14.56.36.png

Unfortunately, actually selecting the new 29.88 timing in SysPrefs simply causes the display to start cycling quickly between off and black-screen-with-backlight, as described earlier in the thread. wtf.

Screen Shot 2020-03-25 at 15.06.32.png
 

joevt

Contributor
Jun 21, 2012
6,622
4,062
Can you give AGDCDiagnose output for the 4K 60Hz mode that you show in the screenshot and then the 30Hz mode so we can compare?
 

joevt

Contributor
Jun 21, 2012
6,622
4,062
Here it is in the "broken and flashing" state, 7680 × 4320 HiDPI@2× 29.88Hz:
I'll have a look at this later today, but for now, have you tried a different cable? What cable/adapter are you using with the Dell 8K? Some cables I got from Dell have failed in the past, but maybe their DisplayPort 1.4 cables are better.
What are the three GPUs that you have?
 

elliottcable

macrumors member
Original poster
Apr 7, 2007
41
7
Chicago, IL
Vega II Duo (PCIe slots 1 & 2), and WX 9100 (PCIe slot 5)

Cable with the above AGDCiagnose is a USB-C to DisplayPort cable between the Vega II Duo's port-two and the Dell UP3218K.

(Also, dude, thank you so much for your help. I see you all over the web fiddling with macOS graphics and such; it must be a sizable time-investment. You don't have to do this, heh!)

Edit 1: Also tried this exact configuration with another DisplayPort 1.4 cable I have, with both A. a USB-C-to-female-DisplayPort adapter connected to the Vega II Duo, and B. a MiniDisplayPort-to-DisplayPort adapter connected to the WX 9100. Unfortunately, doesn't seem to be the cable, or the graphics-card.

The only part of the setup I can't really swap out is the 8k display itself; however, it renders at 8k just fine under Windows, so I suspect that's not it? o_O
 
Last edited:
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.