Connecting multiple Macs to Pro Display XDR

[jaeroner3653]

Yes the usbc's on the back of the XDR do work when connected directly to the pc with the WSJEOG without using the switch. strange....

 

[jaeroner3653]

Ill have a play with the different options for connecting and report back.

Update: The switch does not seem to enable me to use the USB c's on the XDR when switching to PC. or power anything from the switches other port when using pc or mac.

my motherboard is here

 

[fpenta]

Great news, everyone! I've finally found a solution to properly and reliably switch a Pro Display XDR between a Mac and a PC, the latter being connected with a bidirectional DisplayPort-to-USB-C cable.

It's this product: Cable Matters 20Gbps USB-C Switch

✅ 6K@60Hz from both Mac and PC
✅ Switches quickly (~3 seconds)
✅ Works every time (as opposed to Sabrent's Thunderbolt 4 KVM)
✅ Not expensive
✅ Good cable length
✅ Not external power supply required

Important to note:

• It's a USB-C switch, not a Thunderbolt switch. Despite this, System Profiler shows the Pro Display XDR as being connected in "Thunderbolt 3" mode.
• The switch didn't seem to work with Thunderbolt cables connected directly to it (but that may have been a cable issue).
• The USB-C cable connecting to the switch needs to support a data rate of 20gbps. The two included cables do that. If the cable only supports 10gbps, there will either be no connection (black screen), lots of flickering or even a kernel panic. That being said, I've had success with a short USB-C cable that was only rated at 10gbps (but did connect at 20gbps).
• When using a Thunderbolt Dock between the Mac and the Switch, make sure to connect the switch to one of the Thunderbolt ports.
• HDR works fine from the Mac, but Windows stopped showing it as supported after some Nvidia driver update or so. I don't care enough to investigate. Interestingly enough, the Nvidia driver panel allows switching to 12 bits per channel.

I use the switch like this: Mac Studio -> Thunderbolt 3 Dock -> Cable Matters Switch -> Pro Display XDR
Multiple Thunderbolt docks seem to work in that configuration; I've tried both a Promise TD-300 (JHL6540 I believe) and a Orico TB3-S2 (JHL7440).

Note regarding availability: The switch is sometimes out of stock and doesn't seem to be available outside the US (yet). I managed to buy a used one on Amazon, which for some reason does ship to Europe.

I can confirm this switch is perfectly working on both Studio Display and Pro Display XDR with also HDR supported with Windows (need to install bootcamp)! Thanks so much!

 

[petardosh]

Hi everyone,

I decided to give the Cable Matters USB4 switch a try to get rid of the manual unplug and re-plug chore I have with my two Macbooks (M1 and M4) for the last four years. Both are connected to a Anker Thunderbolt 4 Mini Dock, which then connects to the Apple Pro Display XDR. The XDR serves as USB hub for devices shared by both Macs (Logitech 4K cam, keyboard, trackpad and audio device).

The switch works smoothly, even more reliable than the manual replugging somehow. What I don't understand is that the System Profiler reports the XDR connected to my Mac using Thunderbolt 3. Even the Logictech cam is reported to be connected with USB 3.1, just as with using a single Thunderbolt 3 cable before.

The switch is limited to 20Gbps and the Cable Matters Knowledge Article states that it doesn't support Thunderbolt 3. I was expecting to see something like USB-C show up in the System Profiler. I was trying AGDCDiagnose to see if DSC is used but it doesn't work with ARM Macs.

Is there a way to see what kind of connection is actually used and whether bandwidth is reduced?

 

[PaulD-UK]

@petardosh As I understand it, the Pro XDR Display runs in (dual-channel) TB3 mode when the computer it is connected to has a GPU which doesn't support DSC.

If the computer supports DSC, which Apple silicon Macs do, it runs using USB-C Alt-mode DP.

One way you can tell visually if a monitor is running at full resolution 10 bit colour is described in this post, in a thread about testing another 6K display.
You have to display the downloaded image at the highest resolution of the monitor (6K), and display the image at 100%.

One of the conclusions of that thread is that 6K HDR seems to need a TB 5 computer and TB 5 cable to the computer to provide enough bandwidth on that monitor, with TB 4/USB4 cables not giving enough bandwidth for HDR.

 

[petardosh]

Thanks @PaulD-UK ! The image from the other thread didn't show any artefacts or similar as mentioned in the other thread. Also wasn't aware that my XDR was running using DSC all along. In that case 20 Gbps should be enough as the XDR requires only ~13 Gbps with DSC for full resolution video stream.

I did another test to see if I can remove one Anker Dock to reduce desk clutter. Unfortunately this is where the 20 Gbps limitation starts to be noticeable. When running the single dock through the switch, write speeds on my TB4 HDD are reduced by 1/3. Now I'm torn between keeping the switch or waiting for the USB4 40 Gbps switch Cable Matters announced. But then, I've been waiting four years for this switch and def don't want to wait that long again. 😁

Edit: Cable Matters said the 40Gbps USB switch will ship in Q2 2026.