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henrymyf

macrumors regular
Dec 2, 2015
142
58
You have to think about what is supported by the GPU and what is supported by the display.

Intel GPUs support DisplayPort 1.2 (Ice Lake supports DisplayPort 1.4 and DSC but no Apple Mac uses that yet).
AMD GPUs before Navi support DisplayPort 1.4 without DSC (and Nvidia GPUs before RTX).
AMD GPUs starting with Navi support DisplayPort 1.4 with DSC (and Nvidia GPUs starting with RTX).

If you're including Thunderbolt, then some Thunderbolt controllers (Alpine Ridge, Falcon Ridge) support only DisplayPort 1.2 and some support DisplayPort 1.4 (Titan Ridge).
If you have a DisplayPort 1.4 GPU connected to an Alpine Ridge Thunderbolt controller (such as early Thunderbolt 3 Macs), then you can only get DisplayPort 1.2 out of the Thunderbolt controller.
Thanks for such detailed reply! I think I'm getting more and more clear with such subject. If you don't mind, I would like to keep asking some additional questions:

1. From what I saw from the specs of DP 1.4, that with DSC, we could only get 8K 60Hz 8Bit, so is this the reason why Apple chose 6K 10Bit HDR for XDR monitor?

2. DP 2.0 achieved 77 Gbps effective bandwidth only from bi-driectional to single-direction, so does it mean that the physical bandwidth is not upgraded compared with DP 1.4? I mean, after all, TB requires double direction, so that those eGPU docks could be utilized with various of accessories..

3. Could you predict a little bit about the future product line up of Apple? I guess the nano-texture option might got extended to MacBook and iMac, and the Pro Display might get two more sizes, such as 27 inch and 45 inch, for different applications..
 

joevt

Contributor
Jun 21, 2012
6,736
4,098
1. From what I saw from the specs of DP 1.4, that with DSC, we could only get 8K 60Hz 8Bit,
The bandwidth of HBR3 is 4 lanes * 8.1 Gb/s * 8b/10b = 25.92 Gbps.
DSC can effectively triple that: 77.76 Gbps (nearly identical to UHBR 20 link rate of DisplayPort 2.0)
8K 60Hz using CVT-RB2 timing requires 2068.68 MHz pixel clock. At 12 bpc or 36 bpp, that is 74.472 Gbps.

This matches the table at 5.1 Refresh frequency limits for standard video
It shows HBR2 can do 8K60 8 bpc using HBR2 link rate. Since HBR3 is 50% more bandwidth than HBR2, then it means HBR3 can do that at 12 bpc.

so is this the reason why Apple chose 6K 10Bit HDR for XDR monitor?
Apple chose 6K 10 bpc HDR for the XDR because they wanted it to also work with GPUs that do not support DSC. With 10 bpc, 6K was the max that could fit in a Thunderbolt 3 cable (with some left over bandwidth for PCIe connection to the USB controller to allow USB speeds around that of USB 2.0).

I think there was very little incentive to support DSC in comparison.

2. DP 2.0 achieved 77 Gbps effective bandwidth only from bi-driectional to single-direction, so does it mean that the physical bandwidth is not upgraded compared with DP 1.4? I mean, after all, TB requires double direction, so that those eGPU docks could be utilized with various of accessories..
All versions of DisplayPort are single direction. You are confusing Thunderbolt and DisplayPort.
  • USB 3.0 is one lane of 5 Gbps (8b/10b) in both directions (the two remaining lanes can be used for DisplayPort).
  • DisplayPort 1.2 is up to four lanes of 5.4 Gbps (8b/10b) in one direction.
  • DisplayPort 1.4 is up to four lanes of 8.1 Gbps (8b/10b) in one direction.
  • USB 3.2 gen 2 is up two lanes of 10 Gbps (128b/132b) in both directions (if two lanes are used for USB, then the two remaining lanes can be used for DisplayPort).
  • Thunderbolt 2 is up to two lanes of 10.3125 Gbps (64b/66b) in both directions.
  • USB4 gen 3 is up to two lanes of 20 Gbps (128b/132b or 64b/66b) in both directions.
  • Thunderbolt 3 is up to two lanes of 20.625 Gbps (64b/66b) in both directions.
  • DisplayPort 2.0 is up to four lanes of 20 Gbps (128b/132b) in one direction.
Thunderbolt 3 is slightly faster than DisplayPort 2.0 for a single lane, but DisplayPort 2.0 has all four lanes going in one direction so it's actually twice as fast as Thunderbolt 3. Plus DisplayPort 2.0 also supports DSC which can then effectively triple its bandwidth.

3. Could you predict a little bit about the future product line up of Apple? I guess the nano-texture option might got extended to MacBook and iMac, and the Pro Display might get two more sizes, such as 27 inch and 45 inch, for different applications..
I'm not sure nano-texture would be applied to anything else, especially not a laptop - the price increase would be nuts - hmm - maybe Apple would do that... If Apple makes any other displays, they would probably want the size to correspond to the number of pixels for a Retina display. So a 27 inch would be 5K and a 45 inch would be 8K. 8K would be for DSC GPUs only, or Thunderbolt4, or DisplayPort 2.0 - I don't think Apple would do dual cable but they might do Thunderbolt dual tile to allow 5K and 6K support for older Macs - they've already done this for the 6K.

Apple will have to make an 8K one day - because 8K exists for TVs.
 

Nik

macrumors 6502a
Jun 3, 2007
677
1,340
France
Is there a TL;DR to all of this tech talk? ?

1. Without Titan Ridge: Can the XDR be driven with a 2080 TI at 6k via the USB-C Port with a normal Windows PC or not? Doesn't have to be HDR.

2. Without Titan Ridge: Can the XDR be driven at 4k with e.g. a 1070 and a DisplayPort to USB-C Cable? If so, which one?

Thank you!
 
Last edited:

joevt

Contributor
Jun 21, 2012
6,736
4,098
Is there a TL;DR to all of this tech talk? ?

1. Without Titan Ridge: Can the XDR be driven with a 2080 TI at 6k via the USB-C Port with a normal Windows PC or not? Doesn't have to be HDR.

2. Without Titan Ridge: Can the XDR be driven at 4k with e.g. a 1070 and a DisplayPort to USB-C Cable? If so, which one?
1. Yes. You can also get 6K from the DisplayPort outputs using a bidirectional USB-C to DisplayPort cable (but you'll be missing the USB features).
2. Yes. A bidirectional USB-C to DisplayPort cable from Moshi (VESA certified for HBR3) or Monoprice (HBR2).
 
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Nik

macrumors 6502a
Jun 3, 2007
677
1,340
France
1. Yes. You can also get 6K from the DisplayPort outputs using a bidirectional USB-C to DisplayPort cable (but you'll be missing the USB features).
2. Yes. A bidirectional USB-C to DisplayPort cable from Moshi (VESA certified for HBR3) or Monoprice (HBR2).

Thank you. I greatly appreciate your help!

With regards to the 2080 TI USB-C socket:
Can I use the Apple-provided cable and directly connect it to the 2080 TI USB-C Port? If not, what cable do I need for this?

Or does the Moshi Cable also work for 6k and the 2080 TI?
 

joevt

Contributor
Jun 21, 2012
6,736
4,098
Thank you. I greatly appreciate your help!

With regards to the 2080 TI USB-C socket:
Can I use the Apple-provided cable and directly connect it to the 2080 TI USB-C Port? If not, what cable do I need for this?

Or does the Moshi Cable also work for 6k and the 2080 TI?
Both cables should work.
 

Nik

macrumors 6502a
Jun 3, 2007
677
1,340
France
Both cables should work.

1.
If you don't mind, I have one more question: I currently have the GeForce 1070. This one should be able to drive the XDR Display with 6k at 60HZ or doesn't it? If not, 4k should suffice. Moshi • USB-C To Display Port • 1.5m/5ft • 5K@60Hz • VESA Certified: https://www.ebay.de/itm/Moshi-USB-C...686780?hash=item1a92c7557c:g:cfkAAOSw8qBeV3UN

1070 Specs:

I'd like to hold out for the 3080 TI which seems to be around the corner before I spend 1.2k$ on a GPU which is to be replaced just a few months later; I'd like to use my 1070 until then.

2.
Did you try the Apple provided USB-C Cable with the XDR and the 2080 TI to confirm that it works?

3.
What about brightness control? Does that work when connecting to a 2080 TI via the USB-C Port?


Thank you very much for your help!
 
Last edited:

joevt

Contributor
Jun 21, 2012
6,736
4,098
1.
If you don't mind, I have one more question: I currently have the GeForce 1070. This one should be able to drive the XDR Display with 6k at 60HZ or doesn't it? If not, 4k should suffice. Moshi • USB-C To Display Port • 1.5m/5ft • 5K@60Hz • VESA Certified: https://www.ebay.de/itm/Moshi-USB-C...686780?hash=item1a92c7557c:g:cfkAAOSw8qBeV3UN

1070 Specs:

I'd like to hold out for the 3080 TI which seems to be around the corner before I spend 1.2k$ on a GPU which is to be replaced just a few months later; I'd like to use my 1070 until then.
Only the Navi, RTX, and Ice Lake GPUs currently support Display Stream Compression (DSC) which is required for single cable (non-Thunderbolt) connection to obtain 6K 60 Hz (DisplayPort 1.4 HBR2 DSC).

Without DSC, you need a Titan Ridge controller with special firmware or software to enable dual HBR3 connection over Thunderbolt for 6K 60Hz. I don't think that firmware / software exists for anything other than Mac or Blackmagic eGPU Titan Ridge controllers.

I don't think anyone has shown that the XDR can support a single cable HBR3 connection yet (DisplayPort 1.4 without DSC). If it could, then you could get 6K 60Hz 6 bpc. 5K 60Hz 6 bpc HBR2 has been shown to work with the XDR.

2.
Did you try the Apple provided USB-C Cable with the XDR and the 2080 TI to confirm that it works?
Someone else said it works #18 for USB-C ports.
That's interesting because with the LG UltraFine 4K display, there's different cables for USB-C and Thunderbolt. #11

3.
What about brightness control? Does that work when connecting to a 2080 TI via the USB-C Port?
Brightness control requires that you install Boot Camp drivers.
 

Nik

macrumors 6502a
Jun 3, 2007
677
1,340
France
I have connected the 2080 TI with the included XDR Display cable.

It does _not_ work. The display isn't recognized at all.


Furthermore, I cannot install the Bootcamp drivers on my PC since it requires extended privileges; it is asking me to use the exe which does not work.
 

watera

macrumors newbie
Apr 27, 2020
6
1
Florida, USA
I have connected the 2080 TI with the included XDR Display cable.

It does _not_ work. The display isn't recognized at all.


Furthermore, I cannot install the Bootcamp drivers on my PC since it requires extended privileges; it is asking me to use the exe which does not work.
This is for future reference for anyone that wants to install the BootCamp drivers.

So to install the Bootcamp drivers, run "Windows Powershell" or "CMD" as an administrator. Then "cd" into the folder with the BootCamp.msi file. Then run it by typing in "./BootCamp.msi".


-

I have a question, is it confirmed that the RTX2080Ti and the Moshi Bi-directional DisplayPort to USB C cable works with the Pro display XDR?
 
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henrymyf

macrumors regular
Dec 2, 2015
142
58
This is for future reference for anyone that wants to install the BootCamp drivers.

So to install the Bootcamp drivers, run "Windows Powershell" or "CMD" as an administrator. Then "cd" into the folder with the BootCamp.msi file. Then run it by typing in "./BootCamp.msi".

This is very important information. I think anyone who wants to install Bootcamp on non-Apple computers would need this piece of info. Thanks for the illustration~!!
 

pretzelFTW

macrumors newbie
Feb 10, 2020
8
3
I have connected the 2080 TI with the included XDR Display cable.

It does _not_ work. The display isn't recognized at all.


Furthermore, I cannot install the Bootcamp drivers on my PC since it requires extended privileges; it is asking me to use the exe which does not work.

The included XDR display cable is a Thunderbolt cable. It cannot be used to connect the Pro Display XDR to a 2080 Ti. The 2080 Ti does not support Thunderbolt

You need a USB-C cable that supports USB 3.1 Gen 2 (a.k.a. SuperSpeed+, 10Gbps).
 

ksc323

macrumors newbie
Jun 10, 2015
4
0
This is for future reference for anyone that wants to install the BootCamp drivers.

So to install the Bootcamp drivers, run "Windows Powershell" or "CMD" as an administrator. Then "cd" into the folder with the BootCamp.msi file. Then run it by typing in "./BootCamp.msi".


-

I have a question, is it confirmed that the RTX2080Ti and the Moshi Bi-directional DisplayPort to USB C cable works with the Pro display XDR?
yeah it works. I can confirm that hdr even works with appropriate contents by toggling it.
 

watera

macrumors newbie
Apr 27, 2020
6
1
Florida, USA
Just got the cable Moshi Bidirectional DisplayPort to USB C cable today, and can confirm that it works with the RTX2080Ti VirtualLink DisplayPort port!
 
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joevt

Contributor
Jun 21, 2012
6,736
4,098
Just got the cable Moshi Bidirectional DisplayPort to USB C cable today, and can confirm that it works with the RTX2080Ti VirtualLink port!
Virtual Link Port + USB-C to DisplayPort cable means you are using a DisplayPort display?
Or did you mean that you connected the USB-C to DisplayPort cable to a DisplayPort port of the RTX to connect it to the XDR?
If you have an RTX with USB-C port, then a USB-C cable from the Virtual Link port would be better for the XDR so you can use the USB features of the display.
 

watera

macrumors newbie
Apr 27, 2020
6
1
Florida, USA
Virtual Link Port + USB-C to DisplayPort cable means you are using a DisplayPort display?
Or did you mean that you connected the USB-C to DisplayPort cable to a DisplayPort port of the RTX to connect it to the XDR?
If you have an RTX with USB-C port, then a USB-C cable from the Virtual Link port would be better for the XDR so you can use the USB features of the display.
My bad, I meant that I connected the cable to the DisplayPort port of the RTX.

If I were to use the USB C port, what are compatible cables?
 

joevt

Contributor
Jun 21, 2012
6,736
4,098
My bad, I meant that I connected the cable to the DisplayPort port of the RTX.

If I were to use the USB C port, what are compatible cables?
Any USB-C cable capable of USB 3.1 gen 2 or DisplayPort 1.4 should work. This was mentioned previously #45

Someone said the Thunderbolt cable that comes with the XDR worked with the W5700 but I didn't get confirmation. People in this thread said it doesn't work with the RTX. Have you tried the XDR's Thunderbolt cable?

One person said that methods to combine USB and DisplayPort to USB-C for XDR from RTX or Navi non-USB-C ports don't work but they didn't supply evidence (only HBR2 and USB 2.0 is required but DSC of DisplayPort 1.4 might not pass through these options that were created for DisplayPort 1.2):
1) Huawei VR 2 Computer Connection Cable
2) Wacom Link Plus
3) Sunix UPD2018
4) Delock 89582
5) Belkin Charge and Sync Cable for Huawei VR Glass (this one is new - alternative to the Huawei cable - hasn't been tested with the XDR)
6) Bizlink VirtualLink™ Interface Adapter (supports DisplayPort 1.4 but doesn't exist)
 

watera

macrumors newbie
Apr 27, 2020
6
1
Florida, USA
Any USB-C cable capable of USB 3.1 gen 2 or DisplayPort 1.4 should work. This was mentioned previously #45

Someone said the Thunderbolt cable that comes with the XDR worked with the W5700 but I didn't get confirmation. People in this thread said it doesn't work with the RTX. Have you tried the XDR's Thunderbolt cable?

One person said that methods to combine USB and DisplayPort to USB-C for XDR from RTX or Navi non-USB-C ports don't work but they didn't supply evidence (only HBR2 and USB 2.0 is required but DSC of DisplayPort 1.4 might not pass through these options that were created for DisplayPort 1.2):
1) Huawei VR 2 Computer Connection Cable
2) Wacom Link Plus
3) Sunix UPD2018
4) Delock 89582
5) Belkin Charge and Sync Cable for Huawei VR Glass (this one is new - alternative to the Huawei cable - hasn't been tested with the XDR)
6) Bizlink VirtualLink™ Interface Adapter (supports DisplayPort 1.4 but doesn't exist)

Based on my experience, the XDR's Thunderbolt cable does not work with the VirtualLink port.
 

Performat

macrumors newbie
May 8, 2011
29
1
I'm on a PC, running the XDR off the USB-C port of a Nvidia 2070 Super, using a USB 3.1 gen 2 cable. Everything works great @ 6K, amazing!

There is one annoying thing: I don't get a boot screen, so I can't select the boot drive or access the BIOS. The XDR only turns on when Windows is launched, on the account login screen. FWIW, this issue doesn't reproduce with the LG UltraFine 5K.

Is this something you're seeing too?
 

joevt

Contributor
Jun 21, 2012
6,736
4,098
I'm on a PC, running the XDR off the USB-C port of a Nvidia 2070 Super, using a USB 3.1 gen 2 cable. Everything works great @ 6K, amazing!

There is one annoying thing: I don't get a boot screen, so I can't select the boot drive or access the BIOS. The XDR only turns on when Windows is launched, on the account login screen. FWIW, this issue doesn't reproduce with the LG UltraFine 5K.

Is this something you're seeing too?
To be clear, you get a boot screen on the LG UltraFine 5K connected to the USB-C port of the Nvidia RTX 2070 Super? What resolution do you think it's using?

Differences between LG and XDR: the XDR is larger, supports DisplayPort 1.4 and DSC. The XDR has timings for sub 6K resolutions that should work (1440p, 4K, 5K). The timings might not match CVT-RB timings, but that shouldn't matter. The XDR is missing 640x480 Established Timing that the LG has.

I don't think I've seen anyone test custom resolutions/timings/refresh rates on the XDR yet.
 

Performat

macrumors newbie
May 8, 2011
29
1
To be clear, you get a boot screen on the LG UltraFine 5K connected to the USB-C port of the Nvidia RTX 2070 Super? What resolution do you think it's using?
Correct! Since the display has no buttons or menu, and that I can't change the resolution form the BIOS of my motherboard, I really can't tell unfortunately. It's pretty low obviously, but I can't tell how low exactly.

Where can I see all the timings supported by a given display? So I could run this on both displays and see which ones the XDR might be missing.
 

Taras F

macrumors newbie
Oct 22, 2020
5
2
This thread was the most useful source for me to get my XDR to work with Nvidia card in Windows. So I would like to share my experience.

Apple XDR manual says that "Pro Display XDR requires a GPU capable of supporting DisplayPort 1.4 with Display Stream Compression (DSC) and Forward Error Correction (FEC), or a GPU supporting DisplayPort 1.4 with HBR3 link rate and Thunderbolt Titan Ridge for native 6K resolution... You can connect Pro Display XDR to a Windows or Linux PC equipped with a GPU that supports DisplayPort over Thunderbolt or DisplayPort Alt-mode over USB-C."

I had Nvidia Titan V and Windows 10 x64. Titan V is a pretty rare card so I had no info whether it supports DSC or not. According to the open sources HBR3 is only supported by DisplayPort 1.3 and up (1.4) and Thunderbolt 3 only supports DisplayPort 1.2. Nvidia presentation says that DSC has been introduced since RTX 20xx series GPU and Titan V is Volta GPU which was released a bit earlier than those. My setup with Titan V and Apple XDR could never run at native 6K 12bit @60Hz but had always been limited to 5K 6bit @60Hz max. And that was HBR2 connection (as per GPU-Z utility) even though the card supported DisplayPort 1.4 and hence HBR3. I was able to run dual DisplayPort configuration via TitanRidge DisplayPort-in connections and -out to Thunderbolt-3 using ASUS ThunderboltEX 3-TR card however the whole thing was fiddly and the display always went off upon Windows boot (on the second display I was able to see Apple XDR was connected but I could not check the enable box in Nvidia driver's multidisplay setup tab). This could be the 1st working solution as per Apple documentation - "Pro Display XDR requires a ... GPU supporting DisplayPort 1.4 with HBR3 link rate and Thunderbolt Titan Ridge for native 6K resolution". Maybe I needed more time to get it sorted with Nvidia drivers but I gave up and went the 2nd working solution getting a new card which supported DSC. So I've upgraded my video card to the new Nvidia RTX 30xx series - RTX 3090.

RTX 3090 does fully work with Apple XDR at native 6K 12bit @60Hz, HDR available. The display identifies itself, no need to change or correct anything. With Huawei VR 2 Computer Connection Cable and Apple BootCamp installed full functionality is enabled: USB ports and the display setup (brightness control, display color scheme presets).

I can concur that at least 2 cables work:
- Moshi 5K. I have tested it only with Titan V so it works up to 5K 6bit @60Hz max. I assume it may work with the native resolution on newer video cards but there will be no USB support.
- Huawei VR 2 Computer Connection Cable. This cable works with Apple XDR at native 6K 12bit @60Hz, HDR mode can be enabled also. And that's the best option as it enables USB support on Apple XDR and thus makes it possible to install Apple Bootcamp to control the display settings.
 
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Taras F

macrumors newbie
Oct 22, 2020
5
2
But where did you get 12 bits? XDR display is 10 bit.
Just selected in the options. Here are the screens of the current setup.
 

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