MP All Models SOLVED: 8k Displays Running on Mac Pro? Any? What Video cards would work that support 8k HDMI 2.1/Displayport 1.4/2.0 displays on Mac Pro? YES you can

[pkamb]

Soooo. This was disappointing as the display is crazy bright! The colors are crazy vibrant! Also, from a desktop stand point, a single 8k display is bigger than my 6 30" Cinema displays. It's literally the same horizontal resolution and ~2.7x the vertical resolution.

that's incredible. Have you posted a pic of the 6 30" hardware yet?

 

[ZombiePhysicist]

Made immediately available in the Current Resolutions tab. Well, sort of immediately. SwitchResX forces some changes to the display settings, causing macOS to recheck all the modes from the EDID and the override, which causes SwitchResX to load the new list of modes from the display (the SwitchResX tab will switch from Custom Resolutions to Display Information or something).


Every custom 4K timing mode is going to add a bunch scaled modes - one for each scaled resolution multiplied by the number of 4K refresh rates.


I've noticed that Big Sur and Monterey (or just Big Sur? I haven't done a lot of testing in Monterey) does some display connection caching so I sometimes need to disconnect and reconnect the display. It helps to have a second display, or better yet, use Screen Sharing on a different Mac to do the display mode changing tests. If the screen is black, screen sharing will at least show if macOS thinks the mode is working by changing the size of the screen sharing window.


So 4K120 is using 4:2:0 8bpc as expected for 1188MHz pixel clock from the HDMI port of the 6900. Things will get more interesting when you switch to USB-C/DisplayPort.


Yes, create CVT-RB timings for 8K30 and 8K60. They will have pixel clock of ≈ 1030MHz and 2090MHz. The first may be useful for DisplayPort since it doesn't require DSC for RGB 8bpc. The second doesn't require DSC for 4:2:0 8bpc (not sure if I've every seen DisplayPort output 4:2:0 on a Mac - it requires DisplayPort 1.4 which some Macs support).


You mean 4096x2160. 4096x2304 is scaled in your screenshot.


Yes.


Interesting. Maybe 5K is the limit for HDMI output for macOS. You could try CVT-RB for 5152x2898 (the next highest multiple of 32:18).
Should definitely get to writing a Lilu/WhateverGreen patch to remove these limits even if your TV doesn't like 5K input, it might like some other inputs, such as 8K30 4:2:0 8bpc.
You may want to try your TV with Boot Camp to see what the limits of the TV are without the limits of macOS getting in the way.
Another option 6K 25Hz - this will put the pixel clock under 600 MHz which is the HDMI 2.0 limit for RGB 8bpc. The issue is that we don't know if macOS will do 4:2:0 for modes that are not listed in the EDID's 4:2:0 compatibility list. There are no 5K and 6K 16:9 modes in the CTA spec.


Maybe try from Windows to see if it's any difference. Here's a review:
https://www.rtings.com/tv/reviews/samsung/qn900a-8k-qled
They mention that 8K can't do alternating vertical lines (white, black, ...) because Contrast modulation? Not a problem for you until you can get 8K output (Try a test pattern in Windows?)
BGR sub-pixel layout affecting text rendering? Does Apple use sub pixel antialiasing anymore? I don't think so.
The review mentions "pixel dithering in the shadows".
Do you have input set to "PC" and "Input Signal Plus" enabled?

HOLY ****! I got it to work!?!?!

I don't know why/how, but it works at 8k at 60hz. (Although the screen seems to blank and redraw every so often and the trick to make it stop is to set it to some other setting that works, then back to the 8k@60hz one, 2 or 3 times, and that seems to make the blanking/resyncing stop).

So short version (is more succinctly put in post below) is I got it to work from HDMI port 2 (why does port 2 make a difference from port 1??) on the AMD 6900. Before I was trying HDMI port 1 and it wasn't working. The weird thing is right now it only seems to work at 60hz and for some reason I don't get an image at 30hz.

I've attached the AGDCDiagnose.

So weird, I was getting ready to give up, and then these weird/great results.

So few interesting results. I set up boot camp and successfully ran 8k via windows. Zero problems, instantly ran.

It's kind of sad that apple touts 8k work flows, and it's this difficult/shakey to get it going.


Anyway, the Samsung QN900A review you (@joevt) posted was beyond eye opening (thank you) and is the only one that noted what are huge fundamental flaws in the Samsung 8k TV. First, it's not true 8k! For all text you see this artifacting, which apparently is a weird rendering decision that Samsung made for anything that is black/white to throw some inverse white/black around the edges for contrast. This makes text at 8k bleh. Sadly, apparently the only true 8k TV out there is an LG, however, it's RGB sub pixel locations seem to be in the wrong arraignment such that its text looks fuzzy too. In this post I show how things look (worse) under windows. For some reason the text artifacting is worse under windows. The dithering is about the same on windows and macOS.

The article noted that:

The LG QNED99 uses a BGR subpixel layout, which doesn't affect picture quality, but may hurt text clarity when using it as a PC monitor. You can read more about it here.

What is even worse is the absolute crap show dithering is. I've attached screen shots from windows, and this is just not acceptable. EVERYTHING is dithered. That review notes:

Like some of the other 8k TVs we've tested, the Samsung QN900A can't display a perfect 8k image. There's some pixel dithering in the shadows, which is hard to see in the photo, but it's more noticeable in person, especially up close. If you want something that doesn't have any issues displaying native 8k content, then check out the LG QNED99 8k

Perhaps the above is true that dithering is only in the shadows for TV content, but when used from a PC, dithering is basically everywhere. It's just awful and everywhere.

I have half an interest to try the LG because at least it's true 8k, but I worry about the dithering and pixel artifacting on that too.

I get similar results under macOS as under windows. Everything is dithered, and the text has some fuzzy artifacts, although interestingly, far less with small under macOS than under windows. For large text, the artifacting is really quite noticeable under both OSs.

I'm super confused at this point. We've climbed the mountain so to speak, but I may end up returning the TV because the picture isn't good enough, and and now I got to wonder if it would be any better with an 8k LG?

Anyway, I'll post separately the results on macOS.

But it works! I can't believe it, 8k works! w00t!!

Thank you guys for all the help!!!

 

[ZombiePhysicist]

Ok, to get 8k to work on an HDMI based TV/monitor, I was successful with the following equipment:​

(1) 2019 Mac Pro (on macOS 12.1)
(2) AMD Radeon 6900XT (I think reference card) from Sonnet with ports: 1-USBc, 2-DisplayPort 1.4, 1-HDMI2.1: Plug it into DisplayPort port 2 (the DisplayPort port next to the USBc port). The 6900XT card is plugged into slot1 in the Mac Pro. I doubt it makes a difference, but I also have WX9100 plugged into slot 4, and highpoint U.2 7120 in slot 5.
(3) Samsung QN85QN900AFXZA 85" 8K TV with 4-HDMI2.1 ports: plugged into port 2 (and put the TV into Game Mode to reduce text-contrast-artifacts and remove dithering)
(4) Use this CableDeconn DisplayPort 1.4 to HDMI 2.1 cable (firmware version 6.03.146)
(5) You need SwitchResX and need to set it to the following manual settings:

Note that entering the above manual entry does something that makes this following "automatic" entry instantiate and is the actual setting I select under the current resolutions tab:

You may need to switch back and forth from one setting to the above active setting before the 8k "sticks":

Caveat: Changing resolutions seems to get 'iffy'. So going back and for a few times can get it to 'stick'. For now, 30hz does not seem to work but 60hz does, but you know, meh, who cares!

As far as I can tell, I'm the first person on the planet to get an HDMI 8k TV/monitor to work with macOS (thanks to all the help in this forum with huge props/thanks to @joevt who was a major help). That said, I make no promises or guarantees, but the above seems to have worked for me. As always, YMMV.

Ultimately Im guessing it came down to the cable and correct setting on SwitchResX. To test this I'm going to try connecting through my WX9100 Mini DisplayPort card. I'll use that same cable with a Mini DisplayPort to displayport adapter and see if it works just through that old card.

 

[ZombiePhysicist]

Ok a few screen shots from macOS at 8k@60hz on the Samsung QN900A:

You can see the kind of trace edges lines that cast below the text, I guess to help with contrast. It shows more with large text, but it is still there even with small text and makes everything a bit fuzzier.

Here you can see the dithering even on solid colors. Look at the green original poster and blue chevron button below it. See the white'ish half toning dots in it. That kind of halftone dithering is basically EVERYWHERE. It's tougher to capture photographs of it everywhere, but even my zombie character is halftone/dithered, and so is the text in different colors everywhere. It's just awful. It's as if there were only 256 colors or a few thousand colors that get dithered.

Here you can see the window Red yellow and in this case, grey, but basically you can see dithering throughout the screen.

I wonder if the LG QNED99 would do better than the Samsung QN900A as a monitor.

Perhaps one other thing that might be causing some issue is that under macOS the Samsung comes up as a Q900A and not a QN900A under display settings? Could that be part of the problem?

I wonder if you guys think it's worth trying the LG QNED99? Here's a comparison of the 2, and although they reviewed the Samsung better overall as a TV, I think the relevant part of the review as a monitor is this bit:

Although then they say this about the pixel arraignment:

They basically say that the LG pixel order is not good for cleartext (but neither is the Samsung). My guess is it would be equally bad for apple's version of it, although, didnt apple turn that off? That said, the image/text from the LGQNED99 looks sharper than the image from the QN900A from that comparison article (if you blow each up and look around the text in the upper left corners of the image and the text on the street signs.

 

[mattspace]

(2) AMD Radeon 6900XT (I think reference card) from Sonnet with ports: 1-USBc, 2-DisplayPort 1.4, 1-HDMI2.1: Plug it into HDMI port 2 (the HDMI port next to the USBc port)

You might check a couple of your posts as I think this is a typo - do you mean plug into DisplayPort 2, or is there a HDMI port missing on your port listing?

 

[ZombiePhysicist]

You might check a couple of your posts as I think this is a typo - do you mean plug into DisplayPort 2, or is there a HDMI port missing on your port listing?

Thank you, I had it wrong, and fixed it. There is one USBc port, 2 DisplayPort ports, and one HDMI port on the reference AMD 6900 XT. So I mean plug into the 2nd DisplayPort port, the one closer to the USBc port. DisplayPort 1 (the one I initially plugged into) is closer to the HDMI port on the reference card I have.

 

[joevt]

HOLY ****! I got it to work!?!?!

I don't know why/how, but it works at 8k at 60hz.

congrats.

I got it to work from HDMI port 2 (why does port 2 make a difference from port 1??) on the AMD 6900. Before I was trying HDMI port 1 and it wasn't working. The weird thing is right now it only seems to work at 60hz and for some reason I don't get an image at 30hz.

I've attached the AGDCDiagnose.
View attachment 1934468

AGDCDiagnose says you have it connected to DisplayPort.

Anyway, the Samsung QN900A review you (@joevt) posted was beyond eye opening (thank you) and is the only one that noted what are huge fundamental flaws in the Samsung 8k TV. First, it's not true 8k! For all text you see this artifacting, which apparently is a weird rendering decision that Samsung made for anything that is black/white to throw some inverse white/black around the edges for contrast. This makes text at 8k bleh. Sadly, apparently the only true 8k TV out there is an LG, however, it's RGB sub pixel locations seem to be in the wrong arraignment such that its text looks fuzzy too. In this post I show how things look (worse) under windows. For some reason the text artifacting is worse under windows. The dithering is about the same on windows and macOS.

The article noted that:

What is even worse is the absolute crap show dithering is. I've attached screen shots from windows, and this is just not acceptable. EVERYTHING is dithered. That review notes:

Perhaps the above is true that dithering is only in the shadows for TV content, but when used from a PC, dithering is basically everywhere. It's just awful and everywhere.

I have half an interest to try the LG because at least it's true 8k, but I worry about the dithering and pixel artifacting on that too.

I get similar results under macOS as under windows. Everything is dithered, and the text has some fuzzy artifacts, although interestingly, far less with small under macOS than under windows. For large text, the artifacting is really quite noticeable under both OSs.

I'm super confused at this point. We've climbed the mountain so to speak, but I may end up returning the TV because the picture isn't good enough, and and now I got to wonder if it would be any better with an 8k LG?

I wonder if there's any settings to turn off all processing. PC mode? Gaming mode? Low latency mode? Turn off any smart TV garbage. Set picture sharpness to zero. etc.

(4) Use this CableDeconn DisplayPort 1.4 to HDMI 2.1 cable

AGDDiagnose says the cable has a Synaptics VMM6100, similar to the Cable Matters 201388 USB-C to HDMI 2.1 Adapter.

(5) You need SwitchResX and need to set it to the following manual settings:

For MacOS AGDDiagnose says you used a mode with pixel clock 2090.06 MHz instead of 2376 MHz. The connection is 7680x4320 60Hz 8bpc 4:2:0 2090.06 MHz with no DSC.

AGDDiagnose says the adapter doesn't support DSC. Also the EDID provided through the adapter has the 8K50 and 8K60 modes removed, which is why I guess you had to add the mode with SwitchResX. Some adapters will modify the EDID like that. Also, the EDID has the HDR10 VSDB is removed - do you have an HDR option in Displays preferences?

Maybe the adapter needs a firmware update. Use the updater from https://kb.cablematters.com/index.php?View=entry&EntryID=147 to see what the current firmware version is, save the current firmware, and update it. I had 6.03.002 for the Cable Matters 201388 and updated to 6.03.123 which gave me HDR.

For Windows, your screen shot shows 7680x4320 60Hz 10bpc 4:4:4 but doesn't show the pixel clock (use the AMD Radeon Software to find out). There's no way to do this mode without DSC from DisplayPort. Are you using the HDMI port in Windows? I guess there's no reason to try DisplayPort adapter in Windows except to see if it performs better than it does in macOS.

For now, 30hz does not seem to work but 60hz does, but you know, meh, who cares!

Maybe try creating custom CVT-RB 8K30 modes because the default HDMI mode (1188MHz) isn't going to work from DisplayPort without 4:2:2 or 4:2:0 (pixel clock needs to be under 1080 MHz for 4:4:4 or RGB).

Ultimately Im guessing it came down to the cable and correct setting on SwitchResX. To test this I'm going to try connecting through my WX9100 Mini DisplayPort card. I'll use that same cable with a Mini DisplayPort to displayport adapter and see if it works just through that old card.

Since DSC isn't being used, you should get the same result from the WX9100.

Perhaps one other thing that might be causing some issue is that under macOS the Samsung comes up as a Q900A and not a QN900A under display settings? Could that be part of the problem?

The name comes from the EDID which says "Q900A".

 

[Arvine]

Ok a few screen shots from macOS at 8k@60hz on the Samsung QN900A:

This is great news.

- It would be good to confirm what signal the TV receives. If you press home or info button on the TV remote, the TV should show the resolution on the top of the screen, together with the HDMI port number and "Input signal plus", if that is enabled. If you could take a photo of that. Just to double check that there is no downsampling going on.

- I see that the cable you are using is labelled as 8k@30hz, but then in any case supports 8k@60.

- Could you summerize what DP to HDMI adapters you tried, but that didn't work?

- I would be good to see if others can replicate it. I have a similar setup, an AMD 6800 xt with a Samsung 2020 Q800 8K TV.

- Could you share what MacOS version you have?

 

[joevt]

- It would be good to confirm what signal the TV receives. If you press home or info button on the TV remote, the TV should show the resolution on the top of the screen, together with the HDMI port number and "Input signal plus", if that is enabled. If you could take a photo of that. Just to double check that there is no downsampling going on.

Good idea. The AGDCDiagnose says it's 8K60 4:2:0 8bpc 2090.06MHz. That's definitely more bandwidth than HDMI 2.0 TMDS can do, so the TV should report HDMI 2.1 FRL.

The EDID says the TV can do either of these:
1) 40 Gbps FRL (35.56 Gbps of data) with no DSC:
2962MHz 4:2:0 8bpc, 2370MHz 4:2:0 10bpc, 2222MHz 4:2:2 8bpc, 1778MHz 4:2:2 10bpc, 1481MHz 4:4:4 8bpc, 1185 4:4:4 10bpc
2) 24 Gbps FRL (21.33 Gbps of data) with DSC:
2666MHz 8bpp DSC, 1778MHz 12bpp DSC.
I need to read the HDMI 2.1 spec to understand what the DSC stuff is about in the EDID to be sure.

DisplayPort 1.4 is limited to 25.92 Gbps of data so the "no DSC" situation would be:
2160MHz 4:2:0 8bpc, 1728MHz 4:2:0 10bpc, 1620MHz 4:2:2 8bpc, 1296MHz 4:2:2 10bpc, 1080MHz 4:4:4 8bpc, 864 4:4:4 10bpc

The AGDCDiagnose can only give info about the DisplayPort side of the cable/adapter. We don't know what's happening on the HDMI side of the cable/adapter. I wonder if the firmware update utility can show the HDMI info. Does the TV report the info? Does it report DSC info?

- I see that the cable you are using is labelled as 8k@30hz, but then in any case supports 8k@60.

The adapter removed the 8K50 and 8K60 options from the EDID. I suspect this is because of some problem in the adapter and they limited support to 8K30 so people wouldn't complain about the problems. Maybe the firmware updater would fix or change the behavior.

Anyway, with 4:2:0 (12 out of 24 components per 8 pixels), only half the color info is being sent. If the pixel format was 4:4:4 or RGB (without DSC), then 8K30 would be the max, if it can be made to work.

- Could you share what MacOS version you have?

He said macOS 12.1 which is the latest Monterey release.

 

[Pressure]

Try 4K HiDPI and see if the dithering issues are somewhat alleviated.

 

[ZombiePhysicist]

congrats.


AGDCDiagnose says you have it connected to DisplayPort.

Typo on my part, fixed it in my post. Yes it was put in the displayport.

I wonder if there's any settings to turn off all processing. PC mode? Gaming mode? Low latency mode? Turn off any smart TV garbage. Set picture sharpness to zero. etc.

I cant see any options. When I go to picture, my only option is Graphic (which is what it's set to) or Entertainment, which cranks up the brightness and saturation and hue (seemingly).

AGDDiagnose says the cable has a Synaptics VMM6100, similar to the Cable Matters 201388 USB-C to HDMI 2.1 Adapter.

Ill take your word on it, but what I used is the cable I made a link to. I bought it and thats what was shipped to me. I suspect the internals are as you say.

For MacOS AGDDiagnose says you used a mode with pixel clock 2090.06 MHz instead of 2376 MHz. The connection is 7680x4320 60Hz 8bpc 4:2:0 2090.06 MHz with no DSC.

AGDDiagnose says the adapter doesn't support DSC. Also the EDID provided through the adapter has the 8K50 and 8K60 modes removed, which is why I guess you had to add the mode with SwitchResX. Some adapters will modify the EDID like that. Also, the EDID has the HDR10 VSDB is removed - do you have an HDR option in Displays preferences?

HDR does not show up as option. It looks like this:

Maybe the adapter needs a firmware update. Use the updater from https://kb.cablematters.com/index.php?View=entry&EntryID=147 to see what the current firmware version is, save the current firmware, and update it. I had 6.03.002 for the Cable Matters 201388 and updated to 6.03.123 which gave me HDR.

Since it's not the same brand, not sure it makes sense to do a firmware update on it?

For Windows, your screen shot shows 7680x4320 60Hz 10bpc 4:4:4 but doesn't show the pixel clock (use the AMD Radeon Software to find out). There's no way to do this mode without DSC from DisplayPort. Are you using the HDMI port in Windows? I guess there's no reason to try DisplayPort adapter in Windows except to see if it performs better than it does in macOS.

When I was in windows I was using the HDMI port. Was absolutely no issues going from HDMI2.1 port on the 6900XT to the HDMI port on the Samsung TV.

Maybe try creating custom CVT-RB 8K30 modes because the default HDMI mode (1188MHz) isn't going to work from DisplayPort without 4:2:2 or 4:2:0 (pixel clock needs to be under 1080 MHz for 4:4:4 or RGB).

I'm happy to try it, but not sure what settings I should populate it with. This is what's in there currently:

I'm not sure why I have double entire for the 8k 30/60hz where one is active and the other isnt.

60hz inactive:

60hz active:

30hz inactive:

30Hz active:

When I engage the 8k@60z that is active in the current resolution tab it does show the 60.002hz refresh. So I dont understand what's happening and why those popped up and made active after we made our manual entry. It's like playing some weird slot machine when you put in manual entries in the SwitchResX panel, all kinds of other resolutions pop up and get instantiated in seemingly (to me) random ways.

Since DSC isn't being used, you should get the same result from the WX9100.

Unfortunately I dont have the right adapters to test this. The straight Mini DisplayPort to HDMI cable I have doesnt work at all. I suspect youre right.

I just tested moving the cable from DisplayPort 2 back to 1 and now the 8k display works through that port too. So it wasn't a port change. I'm not sure what happened to make this just work all the sudden.

The name comes from the EDID which says "Q900A".

Ah, ok, thanks.

 

[ZombiePhysicist]

This is great news.

- It would be good to confirm what signal the TV receives. If you press home or info button on the TV remote, the TV should show the resolution on the top of the screen, together with the HDMI port number and "Input signal plus", if that is enabled. If you could take a photo of that. Just to double check that there is no downsampling going on.

It shows this:

- I see that the cable you are using is labelled as 8k@30hz, but then in any case supports 8k@60.

Dunno what to say, it outputs like I show.

Weird note about the ports. When I plug the cable back into DisplayPort 1 on the 6900XT, it works as long as I dont change modes. When I then try to change modes using SwitchRezX it doesnt really want to change to any new modes. It fails way more. When I put it back into DisplayPort 2 on the 6900XT, it seems to have a much higher success rate in changing modes.

- Could you summerize what DP to HDMI adapters you tried, but that didn't work?

What I tried is best summarized in this post/table here. Basically nothing worked until I hit this combo here.

- I would be good to see if others can replicate it. I have a similar setup, an AMD 6800 xt with a Samsung 2020 Q800 8K TV.

- Could you share what MacOS version you have?

Monterey 12.1

 

[ZombiePhysicist]

Try 4K HiDPI and see if the dithering issues are somewhat alleviated.

Makes no difference. Even if I drop the resolution down to 1080P I still see the dithering. It's so endemic I wonder if it's some kind of color setting on the Mac or is some setting somewhere on the TV. Problem is the TV menus on picture seem very limited. I turned off all the "contrast" enhancing type settings (and tried varying a lot of them too) but it just seems always there.

@Arvine has a similar set up, so I wonder if he tries it, if he gets similar results.

 

[ZombiePhysicist]

So some new info about the Samsung tv and dithering. It does it all the time. Even it’s own user interface, if you look at it, has no pure colors. Everything is dithered. I’ll post it in a follow up. I cannot believe reviewers didn’t notice such an egregious display flaw. i suspect dithering helps helps with banding uniformity, it’s just a garbage hack technique imo.

 

[joevt]

HDR does not show up as option. It looks like this:
View attachment 1934920

I suppose we could override the EDID that was overridden by the adapter, but first I would try the firmware updater.
Also, I would check the Overrides folder at /Library/Displays/Contents/Resources/Overrides to see if the EDID part that isn't modified by SwitchResX matches the real EDID. You can post a zipped file of that folder and I'll check.

Since it's not the same brand, not sure it makes sense to do a firmware update on it?

I wouldn't worry about. Save the existing firmware, and apply it if there's a problem with the Cable Matters firmware.
At least run the utility to check the current firmware version and see if it reports anything about the signal when the display is connected to the adapter and 6900XT.

I'm happy to try it, but not sure what settings I should populate it with. This is what's in there currently:

I'm not sure why I have double entire for the 8k 30/60hz where one is active and the other isnt.

60hz inactive:
60hz active:
30hz inactive:
30Hz active:

When I engage the 8k@60z that is active in the current resolution tab it does show the 60.002hz refresh. So I dont understand what's happening and why those popped up and made active after we made our manual entry. It's like playing some weird slot machine when you put in manual entries in the SwitchResX panel, all kinds of other resolutions pop up and get instantiated in seemingly (to me) random ways.

You entered these when you were doing the HDMI tests. SwitchResX uses the display's vendor and year/week of manufacture to choose the override file that the settings are saved to. This can be annoying if a display has multiple ports (HDMI / DisplayPort) with different EDIDs but same date. But I don't think that's a problem in your case since all the HDMI ports of your display have the same features - but you can double check by getting EDID for each port (use the HDMI port of the 6900 to make sure the EDID isn't being modified by the DisplayPort adapter).

SwitchResX also saves modes for a display to its own preferences file. So if the overrides file is removed, you may still see modes in the SwitchResX Custom Resolutions tab.

Anyway, the modes that are inactive are the HDMI timings. They use a pixel clock that is higher than CVT-RB and is out of range for the DisplayPort connector. Well, the 30Hz pixel clocks are lower than the 2090MHz of the working 60Hz, but Apple has decided that the 30Hz timing won't get the 4:2:0 option even though the EDID says 8K30 should have the 4:2:0 option. I reported the maximum pixel clocks for DisplayPort 1.4 for each pixel format in my previous post.

For each mode, macOS will report a reason why it is not accepted. Here's how to see that:

1. First, check the log config sudo log config --status --subsystem com.apple.CoreDisplay
2. If it doesn't say DEBUG PERSIST_DEFAULT then do sudo log config --subsystem com.apple.CoreDisplay --mode level:debug
3. Disconnect the display, wait for SwitchResX to register that the display is gone.
4. Enter this to get the start time of the test: timestart="$(date "+%Y-%m-%d %H:%M:%S")"
5. Connect the display
6. Wait for SwitchResX to register that the display is connected, then do timeend="$(date "+%Y-%m-%d %H:%M:%S")"
7. Now you can check the log between the start and end times to see what happened.
8. /usr/bin/log show --start $timestart --end $timeend --info --debug --style compact --source > log_displayport_hdmi_connect_test1.txt

Now you can open the file and look for 7680x4320, match the refresh rate (30Hz) and the pixel clock (1188MHz), and see what it says the reason is for declining the mode.

Unfortunately I dont have the right adapters to test this. The straight Mini DisplayPort to HDMI cable I have doesnt work at all. I suspect youre right.

You'll want to get a MiniDisplayPort (male) to DisplayPort (female) adapter to use your DisplayPort to HDMI adapter cable. I would think the WX9100 would come with some of those (my W5700 came with two of them).

I just tested moving the cable from DisplayPort 2 back to 1 and now the 8k display works through that port too. So it wasn't a port change. I'm not sure what happened to make this just work all the sudden.

Sometimes the "Activate Immediately" button doesn't work in SwitchResX. Disconnecting and reconnecting the display usually works.

It shows this:

Dunno what to say, it outputs like I show.

Not very informative. Maybe need to use some secret key presses.
What about Signal Information: https://www.samsung.com/ph/support/...run-a-self-diagnosis-test-on-your-samsung-tv/
What about the Service Menu:

LG displays show more info:

https://www.reddit.com/r/OLED/comments/fmkgb4

 

[Arvine]

Makes no difference. Even if I drop the resolution down to 1080P I still see the dithering. It's so endemic I wonder if it's some kind of color setting on the Mac or is some setting somewhere on the TV. Problem is the TV menus on picture seem very limited. I turned off all the "contrast" enhancing type settings (and tried varying a lot of them too) but it just seems always there.

@Arvine has a similar set up, so I wonder if he tries it, if he gets similar results.

It is very important that you turn on game mode (turn off internal processing), it is used by gamers to remove the lag. Normally it is the top meny item under settings, you may also find it in some of the setting sub menus.

When I looked at the image I get on my Q800 Samsung TV, I didnt see anything that surprised me. But keep in mind I onlyt got 4K. Each pixel on the TV is made up of three physical dots R, G and B. So if you go very close i e using a magnifying glass, you will see these dots. This will look at bit as dithering if you go very close.

I need to get your adapter before I can try replicating. In any case, it looks like you really got 8K to work!

 

[joevt]

it looks like you really got 8K to work!

But it would be better if we could replace the need for 4:2:0 with DSC - which would require a new adapter (we still haven't seen AGDCDiagnose from the other DisplayPort adapters that @ZombiePhysicist has) or it would require a firmware update.

I am looking at Lilu/WhateverGreen to get the CoreDisplay framework user patches working for Monterey but I'm not sure what is needed. User patches were disabled for Big Sur because of missing map file for dyld shared cache but those now exist so I don't know why user patches were not re-enabled.

 

[ZombiePhysicist]

I’m going out today to see if I can look at an lg tv I noted above to see if it has dithering issue and see if they will let me plug in my laptop to see if it has similar artifacting. If not, I’ll probably return the Samsung and order the LG as a replacement.

Will comeback later and try the suggestions you guys had above. Thanks.

 

[ZombiePhysicist]

So some new info about the Samsung tv and dithering. It does it all the time. Even it’s own user interface, if you look at it, has no pure colors. Everything is dithered. I’ll post it in a follow up. I cannot believe reviewers didn’t notice such an egregious display flaw. i suspect dithering helps helps with banding uniformity, it’s just a garbage hack technique imo.

So to show that dithering is always on, I took a photo of the Samsung UI itself. Here you can see, this is not just some closeup sub pixel issue, it affects large areas. You can see this is a purposeful halftone dithering and this is on parts of Samsung's UI itself. Self generated. My guess is they render their UI at 4k, but issue is always there, regardless of the resolution. Once you know how to look for it, you cannot unsee it, but it particularly is prominent once you get into 8k modes.

Look at the gradient and how the half toning works across.

Also, ever since I moved the cables around, it's hard to get back into the 8k mode and switch ResX keeps saying configuration has been modified blanking my screens resetting the resolutions a bunch. I takes a lot more selecting other resolutions and then back to 8k for it to 'settle' and stay stable than before. I also wonder if booting into windows into 8k mode somehow helps this get more stable?

 

[ZombiePhysicist]

So I went to Best Buy and Costco, none had the LG QNED 99. They had the 4k QNED version which didn't have the dithering issue, and I couldn't put text up, but looked at some of the licensing text from the UI and it didn't exhibit the behavior of the samsung. I think the LGs us an IPS base hardware, which might explain why it's so much better than the samsung. But it looks like it's worth the risk returning the samsung and trying the LG.

In other interesting news, with the DisplayPort to HDMI cable I use on macOS, when using that cable with windows, I get 8k but at 30hz instead of 60.

Also, I cannot seem to get into the service menu as my remote doesn't have a number keypad. It is their solar powered remote that they give you with this TV and its a minimalist remote.

 

[ZombiePhysicist]

Sooo. I was totally wrong about dithering and text and image quality. After futzing around trying to find the service mode, which I still cannot find/figure out, I found how to get into game mode.

The UI on the Samsung is total garbage and non intuitive.

Anyway, after you get it into game mode (thank you @Arvine). NO DITHERING. Also, the text looks really great. I think I can still kind of see the slight banding below text, but it is sooooo slight as to be a non issue. This thing works GREAT as a monitor. MAN I AM SO PSYCHED!

Now I do suspect the LG monitor might even be better. But I love the cheese grater edges of this monitor and the zero bezel, so the quality is totally fine. I also watched some 8k video from YouTube on this. MIND MELTING! There is no going back. 8k is like getting your first SSD. There is no going back!

 

[hardwickj]

@ZombiePhysicist could you summarize what combination of video cards/ports + adapters + cables you ultimately settled on? It appears you were bouncing around a bit while experimenting. Just curious what ultimately worked best for you.

 

[Arvine]

Anyway, after you get it into game mode (thank you @Arvine). NO DITHERING. Also, the text looks really great. I !

Great!

Could you share photos of the screen with game mode on?

A summary of cables, settings etc would be helpful. It would be interesting to learn if the Cable Matters DP 1.4 to HDMI 2.1 also work (according to @joevt it uses the same chip as the one you are using, but should support 8K@60hz.

 

[ZombiePhysicist]

@ZombiePhysicist could you summarize what combination of video cards/ports + adapters + cables you ultimately settled on? It appears you were bouncing around a bit while experimenting. Just curious what ultimately worked best for you.

Great!

Could you share photos of the screen with game mode on?

A summary of cables, settings etc would be helpful. It would be interesting to learn if the Cable Matters DP 1.4 to HDMI 2.1 also work (according to @joevt it uses the same chip as the one you are using, but should support 8K@60hz.

So perhaps Im missing something, but I did make a summary post #128 here, and noted it above earlier? Is there something missing from that post?

If you guys can give me a link to the right CableMatters cable, I'll buy it and do the firmware upgrade on it. Right now my cable is working to give me the 8k, and I don't want to mess with it, just in case there is something weird/special about it making things work.




As for photos, your wish is my command (apologies for all the weird angles, the TV is on the floor in a tight spot waiting for me to mount it):

So here are some of the settings on the TV. They are probably not ideal, but they made the set less SCREAMING BRIGHT and closer to reasonable. I havent gotten into service mode because I don't know how since this remote does not have a keypad. So these are the settings I could find under the normal settings UI (which is dreadful):

First setting, Game Mode: Ok, the biggest trick is how to get to game mode, because game mode is NOT found in the standard picture setting list of options, you get there by selecting settings, but NOT clicking it, and instead moving up a level where there is a list of other things you can click on, and eventually, off screen, you will see a game mode option:

These are my quick expert setting adjustments to keep the screen from blinding me and the colors to be a little less screamy.

Brightness: 34
Contrast: 37
Sharpness: 10
Color: 30
Tint: 0
Local Dimming: High
Contrast Enhancer: Off
White balance: 2 point (only option)
Gamma: BT.1886
BT.1886: 0
Shadow Detail: 0


And lastly, here are a few photos of the text:

Here are 2 really interesting photos:

So if you look at the green "original poster" button and even the little green dot in my zombiephysist avatar, you see a slight checker boarding pattern in the photo> and maybe a subtle one in the grey and white areas around the text. That is an artifact of the photo. I absolutely do not see that with my naked eye. It looks completely solid to the naked eye. Now perhaps that checker boarding is just an artifact of the camera, but I suspect there may be something more to it, in that there is a half toning going on, but the TV does it in a way that you just dont see it with your naked eye, and it looks completely solid.

But you can see, the text looks very solid. Pretty much the same as if I blow it up on my 30" Cinema Display. In fact, here is a similar shot from my Cinema Display for comparison, and you can see the a similar checker boarding occurs in the grey areas although it's more faint in the green:

In both cases on the Samsung and the 30" Cinema Display, it all looks solid and good with your naked eye.


Hope that helps.

 

[joevt]

So perhaps Im missing something, but I did make a summary post #128 here, and noted it above earlier? Is there something missing from that post?

There was an earlier post from you which listed more cables and adapters.
https://forums.macrumors.com/thread...-on-mac-pro-yes-you-can.2309750/post-30712378

You've only shown info for this cable:
https://www.amazon.com/dp/B0994FPCMD CableDeconn DisplayPort 1.4 to HDMI 2.1 8K Cable

We do not have any info (AGDCDiagnose and tests) from you about these:
https://www.amazon.com/dp/B08XFYHFCK CableMatters 101101 8K Mini DP to HDMI Adapter
https://www.amazon.com/dp/B094XDDRL6 CableMatters 101109 8K Mini DP to HDMI Cable
https://www.amazon.com/dp/B08QDV5H4M CableMatters 201362 USB C to 8K HDMI Cable
https://www.amazon.com/dp/B08Y246V8X Sabrent USB Type-C to HDMI 2.1 Adapter

Question about the last test in that post:
this one: "6900XT | USB-c port 4 via DP adapter | TVHDMI2.1 port 1 | FakeAlmost8k | MiniDP1.4 to HDMI2.1 Cable"
How did you connect Mini DP to the USB-C to DP adapter?
You'll need a DisplayPort (male) to Mini-DisplayPort (female) adapter to test your Mini DP adapters and cables with the 6900XT
or a USB-C to Mini-DisplayPort (female) adapter.

If you guys can give me a link to the right CableMatters cable, I'll buy it and do the firmware upgrade on it. Right now my cable is working to give me the 8k, and I don't want to mess with it, just in case there is something weird/special about it making things work.

I would like you to run the utility to get the firmware version from the cable and extract the firmware. You don't need to modify the firmware if you don't want to. I am wondering why the cable doesn't show support for DSC in the AGDCDiagnose output.

Here are some other options:
https://www.amazon.com/dp/B08MSWMXT4 CableMatters 201388 USB C to 8K HDMI Adapter (uses VMM6100)
https://www.amazon.com/dp/B08BX49V5V Club-3D CAC-1085 DisplayPort 1.4 to HDMI 4K120 Adapter (uses Realtek RTD2173)
https://www.amazon.com/dp/B092RD7MQR Club 3D CAC-1586 USB Type-C to HDMI 4K 120Hz Adapter