Two computers and one Studio Display?

[trevor-b]

Thanks for the suggestions. I've ordered the CableDeconn version to see if that makes any difference...here's a short video showing my MBP 14" and the Pro Display connected to the switch with the cable it arrived with and nothing else connected to the hub on the back. It just keeps flickering and the picture goes in and out.

View attachment 2041201

I think you may have a bad unit. I went through 2 Yiwentecs, before finding one that works. They will only work with the the included cable.

btw, there's NO difference other than branding between Yiwentec and CableDeconn. They look exactly similar.

Lots of discussions here and upthread.

 

[alaman64]

Mine would flicker every 30 minutes or so, but not all the time. some days would be fine. I replaced the cabe yesterday with Cable Matters 10 Gbps Gen 2 USB C to USB C Cable 3.3 ft. So far No flickering been 24 hours.

 

[joevt]

There are currently no HDMI 2.0 to DisplayPort or USB-C adapters that can do greater than 4K width. It would be nice to do 5K width even if the refresh rate needs to be reduced to 39Hz.
https://insights.club-3d.com/thread/hdmi-2-1-to-usb-c-displayport-1-4-alt-mode/

CAC-1335 and CAC-1336 are out. Maybe they can do 5K/6K from HDMI to DisplayPort?

 

[citivolus]

The YIWENTEC USB-C switch arrived today and it doesn't work with my MBP 14" and Pro Display XDR. Occasionally I'll get a picture but it has a huge flickering problem and then drops completely. I tried both the USB-C cables it came with and an Apple Thunderbolt 3 cable. Oddly when it occasionally connected, I was able to confirm it saw the Pro Display XDR under Thunderbolt in the Apple System Profiler. I just ordered the Cable Deconn version (a second time) but hope is fading fast. No exit from cable hell for me (yet).

The Cable Deconn version arrived today and so far so good! I even connected it to my MBP 14" and Windows laptop using the USB-C cables from the old YIWENTEC version so clearly there was a difference in the units, even if it was just one being defective. Fingers crossed that this lasts!

BTW it seems to take about 7-8 seconds when I switch to my Mac before the desktop shows up on my Pro Display XDR. Is that typical for those of you with this switch?

 

[Johnf1285]

Anyone still using the magnetic connectors? If so do you use them daily?

It’s such a bummer this display couldn’t accept more than one input. Pretty common feature. But I suppose an Apple display to have this feature hasn’t existed in decades.

 

[tommiy]

@Johnf1285 yes i am using magnetic connectors daily for the last 6 months and have not had any issues as yet.

 

[Johnf1285]

@Johnf1285 yes i am using magnetic connectors daily for the last 6 months and have not had any issues as yet.

Do you swap the connection at the Studio Display itself or between the computers?

 

[trevor-b]

Anyone still using the magnetic connectors? If so do you use them daily?

It’s such a bummer this display couldn’t accept more than one input. Pretty common feature. But I suppose an Apple display to have this feature hasn’t existed in decades.

Any reason to not use the switches? Seems to work well for most people most of the time

 

[Johnf1285]

Any reason to not use the switches? Seems to work well for most people most of the time

Oh, no reason to not use a switch from my perspective. I'm just curious what the magnetic connector experience is like for those who have been using it very frequently.

 

[BeatCrazy]

Oh, no reason to not use a switch from my perspective. I'm just curious what the magnetic connector experience is like for those who have been using it very frequently.

Using the magnetic connectors every day for several months now. I swap between 4+ different source devices and my Apple Studio Display. Every few weeks my 14" MBP doesn't want to output video, but a reboot of the laptop fixes that.

 

[BeatCrazy]

CAC-1335 and CAC-1336 are out. Maybe they can do 5K/6K from HDMI to DisplayPort?

I'll probably pick up a CAC-1336 in the next few weeks. I'll need to (re)assemble a PC with HDMI 2.1 GPU and see if it can drive the Studio Display at 5K/60.

One annoyance with the CAC-1336 - it needs a micro-USB connector for power I am getting so close to ridding my life of micro-USB, and along comes this dumb thing.

 

[joevt]

One annoyance with the CAC-1336 - it needs a micro-USB connector for power I am getting so close to ridding my life of micro-USB, and along comes this dumb thing.

The micro-usb is useful for USB-C displays to support the USB features of the display (audio for displays that use USB audio, camera, USB ports, presets, brightness control, auto display rotate)

 

[BeatCrazy]

The micro-usb is useful for USB-C displays to support the USB features of the display (audio for displays that use USB audio, camera, USB ports, presets, brightness control, auto display rotate)

The micro-USB appears to only used as an auxiliary power source, i.e. you plug it into an AC power source, not necessarily the host PC.

 

[joevt]

The micro-USB appears to only used as an auxiliary power source, i.e. you plug it into an AC power source, not necessarily the host PC.

The CAC-1332 used the micro-USB for power and USB 2.0 data. I hope the CAC-1336 is the same. The product descriptions for both do not mention the USB data functionality but they should if it works for data.

 

[BeatCrazy]

The CAC-1332 used the micro-USB for power and USB 2.0 data. I hope the CAC-1336 is the same. The product descriptions for both do not mention the USB data functionality but they should if it works for data.

The installation guide for the CAC-1336 says:

Connect a power adapter or computer to the USB Type A plug to supply power for the adapter.

Which implies you don't need a data connection in order for it to function as described.

 

[tommiy]

@Johnf1285 At the computer end.

 

[joevt]

Which implies you don't need a data connection in order for it to function as described.

Correct. Having no data is ok if you don't want to use the USB features of the display (for USB audio, keyboard, mouse, camera, brightness control, presets).

 

[BeatCrazy]

Correct. Having no data is ok if you don't want to use the USB features of the display (for USB audio, keyboard, mouse, camera, brightness control, presets).

Why would you say those features require the additional micro-USB connection vs. tunneling over the standard USB-C via DP Alt Mode?

 

[JerryWest44]

Until there is a rock solid TB3/4 video switch for the ASD I went with the following:

Apexsun

2Pack Straight+ Extra 2 Plugs] USB C Magnetic Adapter,24 Pins Type C Support Thunderbolt 4,USB4.0, PD 100W Charge,40Gb/s Data Transfer,8K Video Output Compatible with MacBook and More USB C Devices​

CableMatters TB4 1m cable

[Intel Certified] Cable Matters 40Gbps Thunderbolt 4 Cable 3.3ft with 8K Video and 100W Charging - 1m, Compatible with USB4, Thunderbolt 3 Cable and USB-C​

​

My Dell Latitude 5420 and Mac Studio Ultra drive the ASD to the full 5K resolution.​

 

[joevt]

Why would you say those features require the additional micro-USB connection vs. tunneling over the standard USB-C via DP Alt Mode?

We are talking about HDMI to USB-C adapters like the CAC-1332 and CAC-1336 where the source connection is HDMI. HDMI doesn't have any USB signals that can be used by the USB-C end of the adapter - hence the need for the adapter to have a separate USB connection to support USB features of USB-C DP Alt Mode devices/displays. Otherwise you only get the DisplayPort part of the USB-C DP Alt Mode. USB-C DP Alt Mode also has a USB part.

There's two kinds of USB-C DP Alt Mode:

1. 4 lanes of DisplayPort + USB 2.0, supported by many displays. 4 lanes of HBR2 is enough for 4K60. Add DSC and you can get 5K60 and 6K60. HBR3 + DSC should allow 8K60 if the GPU, adapter, and OS drivers allow it.
2. 2 lanes of DisplayPort + USB 3.x, supported as input to USB-C docks and Titan Ridge and Goshen Ridge based Thunderbolt 3 and Thunderbolt 4 docks.

The CAC-1332 and CAC-1336 should support the first one, 4 lanes of DisplayPort + USB 2.0.

Some displays have a menu option to choose between the first and second mode.

I don't know if there are any devices that can automatically switch from the second mode to the first mode when the USB-C connection doesn't have a USB 3.x capability.

 

[BeatCrazy]

We are talking about HDMI to USB-C adapters like the CAC-1332 and CAC-1336 where the source connection is HDMI. HDMI doesn't have any USB signals that can be used by the USB-C end of the adapter - hence the need for the adapter to have a separate USB connection to support USB features of USB-C DP Alt Mode devices/displays. Otherwise you only get the DisplayPort part of the USB-C DP Alt Mode. USB-C DP Alt Mode also has a USB part.

There's two kinds of USB-C DP Alt Mode:

1. 4 lanes of DisplayPort + USB 2.0, supported by many displays. 4 lanes of HBR2 is enough for 4K60. Add DSC and you can get 5K60 and 6K60. HBR3 + DSC should allow 8K60 if the GPU, adapter, and OS drivers allow it.
2. 2 lanes of DisplayPort + USB 3.x, supported as input to USB-C docks and Titan Ridge and Goshen Ridge based Thunderbolt 3 and Thunderbolt 4 docks.

The CAC-1332 and CAC-1336 should support the first one, 4 lanes of DisplayPort + USB 2.0.

Some displays have a menu option to choose between the first and second mode.

I don't if there are any devices that can automatically switch from the second mode to the first mode when the USB-C connection doesn't have a USB 3.x capability.

I totally blanked out and forgot the source was HDMI. Great explanation and thanks for the reference points!

 

[guitarguy19]

Hey all,

I’m looking to setup what many here have discussed - my personal MacBook Air (2020 Intel i5) and work-provided PC (an HP Zbook i7 G6, which does support TB3) to both work with the ASD via the ‘switch’ method. I’ve got both the “Gen 2” CableDeconn and Yiwentec switches on the way, as well as (2) of the Cable Matters USB C to USB C Monitor Cable 6 ft cables that were referenced on the way…so we shall see! Also planning to use an MX Keys keyboard via the usb hub (with an adapter) in the back of the ASD and hoping that will switch along with the display as others have stated will work. I have a magic trackpad for the MacBook and a regular mouse for the PC so I’m set there (don’t mind keeping both).

I did notice when looking at the cable description that it says “up to 4K @ 60Hz” for the resolution capability. Can anyone explain why this will get recognized as a Thunderbolt device and pass the 5k60 signal through, even though it’s above the spec of the cable?

Very curious!

 

[joevt]

I did notice when looking at the cable description that it says “up to 4K @ 60Hz” for the resolution capability.

Which cables? I don't think USB-C cables should be limited to 4K 60K.

The Apple Studio Display supports DSC, so a HBR2 link rate (used by 4K 60K DisplayPort displays) is sufficient (if DSC is also supported by the OS, drivers, and GPU).

HDMI 2.0 allows 14.4 Gbps.
HBR2 allows 17.28 Gbps.

With DSC each pixel is on average 12 bits (but this can maybe be changed to between 8 and 16 bpp).
Without DSC, each pixel is between 18 and 30 bits (36 and 48 bpp are also options but they usually aren't used since HDR only requires 30bpp = 10bpc)
chroma sub sampling is also an option to reduce bpp. The minimum is 4:2:0 8bpc = 12bpp. 4:2:2 8bpc = 16bpp. Apple's displays don't support chroma sub sampling.

4K60 uses a pixel clock between 522 and 594 MHz.
5K60 is 936 MHz.
6K60 is 1286 MHz.
594 MHz * 24 bpp = 14.3 Gbps (594MHz is HDMI timing - it's limited to 8bpc RGB when HDMI 2.0 or HBR2 are used - 10bpc requires 4:2:2 or 4:2:0 chroma sub sampling)
522 MHz * 30 bpp = 15.7 Gbps
533 MHz * 30 bpp = 16.0 Gbps
936 MHz * 18 bpp = 16.8 Gbps (macOS doesn't support 6bpc).
936 MHz * 12 bpp = 11.2 Gbps (DSC)
1286 MHz * 12 bpp = 15.4 Gbps (DSC)

So you see that a 6K60 display using DSC can use less bandwidth than a 4K60 diplay that doesn't use DSC.

 

[guitarguy19]

Which cables? I don't think USB-C cables should be limited to 4K 60K.

The Apple Studio Display supports DSC, so a HBR2 link rate (used by 4K 60K DisplayPort displays) is sufficient (if DSC is also supported by the OS, drivers, and GPU).

HDMI 2.0 allows 14.4 Gbps.
HBR2 allows 17.28 Gbps.

With DSC each pixel is on average 12 bits (but this can maybe be changed to between 8 and 16 bpp).
Without DSC, each pixel is between 18 and 30 bits (36 and 48 bpp are also options but they usually aren't used since HDR only requires 30bpp = 10bpc)
chroma sub sampling is also an option to reduce bpp. The minimum is 4:2:0 8bpc = 12bpp. 4:2:2 8bpc = 16bpp. Apple's displays don't support chroma sub sampling.

4K60 uses a pixel clock between 522 and 594 MHz.
5K60 is 936 MHz.
6K60 is 1286 MHz.
594 MHz * 24 bpp = 14.3 Gbps (594MHz is HDMI timing - it's limited to 8bpc RGB when HDMI 2.0 or HBR2 are used - 10bpc requires 4:2:2 or 4:2:0 chroma sub sampling)
522 MHz * 30 bpp = 15.7 Gbps
533 MHz * 30 bpp = 16.0 Gbps
936 MHz * 18 bpp = 16.8 Gbps (macOS doesn't support 6bpc).
936 MHz * 12 bpp = 11.2 Gbps (DSC)
1286 MHz * 12 bpp = 15.4 Gbps (DSC)

So you see that a 6K60 display using DSC can use less bandwidth than a 4K60 diplay that doesn't use DSC.

This was the cable, linked up thread by @edanuff as an option that worked:

Cable Matters 20Gbps USB C to USB C Monitor Cable 6 ft / 1.8m with 4K 120Hz & 8K 30Hz, 240W Power Delivery, USB C Video Cable/USB C Display Cable with USB-C 3.2 20Gbps Data Transfer

Cable Matters 20Gbps USB C to USB C Monitor Cable 6 ft / 1.8m with 4K 120Hz & 8K 30Hz, 240W Power Delivery, USB C Video Cable/USB C Display Cable with USB-C 3.2 20Gbps Data Transfer

www.amazon.com

It says 4k60 in the specs, and only 5gbps. But supposedly it can still do 5k60…?

 

[joevt]

It says 4k60 in the specs, and only 5gbps. But supposedly it can still do 5k60…?

So its a USB 5 Gbps cable. 4K60 uses HBR2 link rate which is 5.4 Gbps per lane (DisplayPort has 4 lanes).

5K60 and 6K60 can be supported with HBR2 link rate only if DSC is used (macOS uses 12bpp DSC for the Apple Pro Display XDR and Apple Studio Display) or if color depth is 18bpp (6bpc) (Windows AMD and Nvidia drivers allow selecting 6bpc). If the display supported chroma sub sampling, then 8bpc 4:2:0 can work for 6K60 and 12bpc 4:2:0 or 8bpc 4:2:2 can work for 5K60.

Read my second post at https://insights.club-3d.com/thread/cac-1336-operation/