[joevt]

Maybe not. The CSV-1460 uses DisplayLink which is limited to HBR2 link rate.

I think 5120×2880 refers to dual cable 5K displays where each 2560×2880 half of the display uses a separate DisplayPort 1.2 HBR2 x4 connection.

5120×2160 displays don’t have a dual cable mode unless it’s through a Thunderbolt port (where the Thunderbolt port carries two DisplayPort HBR2 x4 connections – one for each 2560×2160 half of the display). Exactly which display do you have?

5120×2160 60Hz only requires 693 MHz pixel clock which should be doable with HBR2 x4 at 8bpc but I don’t think DisplayLink supports widths greater than 4K. Actually, https://support.displaylink.com/knowledgebase/articles/525038-displaylink-display-resolution-support says DisplayLink can do 5120×1440 60Hz. Maybe it can do 5120×2160 60Hz then (if it allows 8bpc)?

I guess first you should determine if the display will do 5120×2160 using HBR2 link rate from a normal GPU.

[joevt]

If you can get one display to work from the dock, then it means the USB-C port of the laptop that the dock is connected to supports DP Alt Mode. You can also verify this using a USB-C to DisplayPort (CAC-1567) or HDMI (CAC-1504, CAC-2504, CAC-1586, etc.) or DVI (CAC-1510) or VGA (CAC-1502) adapter and connect a display.

The reason you can’t get two displays to work from the dock may be because the displays have a resolution/refresh rate that is too high? What exact Dell displays are you trying to connect?

It appears that the MST hub in the dock only supports DisplayPort 1.2 (HBR2 link rate) and only has two lanes. Two lanes is normal for USB-C docks that support USB 3.x. Your laptop only supports DisplayPort 1.2 so DisplayPort 1.4 support would not help.

You should be able to connect two displays up to 1080p60 using the MST mode. The total pixel clock for both displays should not exceed ≈360 MHz (for 8 bpc color). 1080p60 HDMI is 148.5 MHz but that can be reduced to 133 MHz using CVT-RB2 timing (if the display supports it). 1440p60 is at least 234 MHz so there’s little chance of getting 1440p60 & 1080p60 unless you lower the refresh rate (Intel GPUs don’t support lower bpc).

You can get USB-C docks that have MST hubs with 4 input lanes but those docks only support USB 2.0.

[joevt]

You can e-mail [email protected] and ask for a firmware update of the CAC-1085. I don’t know if it will fix your problem.

On the DisplayPort side:
4K 120Hz 10bpc 4:2:0 (assuming 1188MHz) is possible without DSC using HBR3 link rate but not HBR2.
4:4:4 would require DSC but could work at HBR2 link rate.
GPU-Z in the advanced tab should show the link rate (8.1 Gbps) but I don’t know if Windows shows DSC anywhere. Is there an app that can show DPCD registers in Windows?

On the HDMI side:
It is not possible with a HDMI 2.0 connection without going to 8bpc 4:2:0.
HDMI 2.1 @ 6 Gbps without DSC is sufficient for 10bpc 4:2:0.
10bpc 4:4:4 requires DSC at 6 Gbps or non-DSC at 12 Gbps.
The FreeSync information menu shows some input connection info.
https://www.youtube.com/watch?v=dnUUAZY9HnQ
https://www.reddit.com/r/OLED/comments/kvxamh/ycbcr420_10b_tm_vs_rgb_10b_4l10/
4L10 is 4 lanes at 10 Gbps. HDMI 2.0 is shown as TM which is short for TMDS (3 lanes of 6 Gbps)

Maybe a custom timing of 4K 120Hz using CVT-RB would work better (1098 MHz). Then 4:4:4 can be done using 4L10 instead of 4L12.

Here’s another thread about the CAC-1085 and 4K120 10bpc:
https://insights.club-3d.com/thread/cac-1085-wont-work-at-444/

 

[joevt]

Nvidia GPUs can only connect 4 displays each.

What if you somehow combine 3 monitors to make them appear as a single monitor?
https://www.matrox.com/en/video/products/gxm/triplehead2go-series/dp-edition
But that one only supports two 1920×1200 displays…

Do the Matrox devices use the ViewXpand feature of a Synaptics MST hub?
https://uploadcdn.oneyac.com/attachments/userfile/b4/13/1593672494627_4765.pdf

I can’t find any documentation on ViewXpand. What is the max resolution of ViewXpand? Can it be controlled by software to override the MST features of the hub and make it work as SST? Otherwise it seems like it would only work from a DisplayPort 1.1 port that doesn’t support MST and is limited to HBR link rate. Maybe it works at HBR2 link rate but only if the port doesn’t support MST…

Maybe there are better video wall processors that will support three 1920×1200 displays. There’s a Chinese product named “BIT-MSE-4K60-104PRO”. Is it real? Does it work? I don’t know. Seems expensive? You would need two of them.

Anyway, once the displays are combined, then you can connect both combined displays to Nvidia to mirror them.

[joevt]

For a PC, the CAC-1332 would be better because it includes a USB 2.0 connection that would let you use the USB features of the display (brightness control, audio, camera, presets) if the Boot Camp drivers are installed.

It might still be better for a gaming console, if the Studio Display doesn’t do audio from HDMI/DisplayPort, and the gaming console can do USB audio.

In either case, it might work, or it might not. Thunderbolt displays with no buttons are finicky.

[joevt]

The cables are VESA certified which means they are constructed properly.
 https://www.displayport.org/product-category/cables-adaptors/?ps=cac-2068

[joevt]

Yes.

[joevt]

Thanks for the clarification regarding the image.

About DSC, I’m not sure what the distinction is between 1.1 and 1.2 or what in my discussion  the version number of DSC would affect or applies to. There’s a list of some differences at
https://vesa.org/vesa-display-compression-codecs/
but as far as I know, most solutions that support DSC are using 1.2 for DisplayPort. I would be interested to know of an example of DSC 1.1.

Regarding MST hub connected to Thunderbolt 4 Hub (CSV-1580 or anything else that uses Goshen Ridge) it seems strange to me that the MST hub wouldn’t work to allow multiple displays. Instead of Iris xE, maybe a 690 motherboard with Maple Ridge Thunderbolt 4 add-in card (or built-in Maple Ridge with DisplayPort input for Radeon Navi or Nvidia RTX) might have different behavior? The HP Thunderbolt Dock G2 is an example of a Thunderbolt dock with an MST hub connected to it (internally). It’s Thunderbolt 3 (Titan Ridge) but I would expect Thunderbolt 4 to be just as capable. I was able to connect 3 4K60 HBR2 displays to that. The total output bandwidth exceeds HBR3 so DSC is working.

Regarding using an MST hub to convert HBR2 with DSC to HBR3 without DSC, maybe a better example to illustrate MST hub format conversion is with a two lane USB-C adapter or dock that uses MST to convert two lanes to four lanes. For example, the Apple USB-C Digital AV Multiport Adapter (two lanes of DisplayPort since the other two SuperSpeed lanes are used for USB 3.0) which also supports DSC. Another example is the CalDigit SOHO which contains a two port MST hub. The CAC-1510 or CAC-1010 requires 4 lanes of HBR to do 1440p so two HBR2 or HBR3 lanes from a USB-C dock (that supports USB 3.x) will only allow 720p unless a MST hub is used to convert the two lanes to four lanes of HBR.

[joevt]

All Thunderbolt 4 hubs/docks use a similar amount of power since they all use the same Goshen Ridge Thunderbolt 4 controller. I suppose a dock may use slightly more power since they have additional USB hubs and devices inside.

All Thunderbolt 4 hubs/docks do not require special cooling or fans. At least I haven’t seen any that had fans or vents for a fan. I have an HP Thunderbolt Dock G2 that has a fan but I didn’t know it had a fan until I took it apart.

The power requirements are unclear. It comes with a 100W power supply but says it can supply 60W for host and uses 85W for host and hub. So what about the remaining 15W?

The type-A port can provide up to 900mA @ 5V = 4.5 W. I guess the type-C ports can provide up to 15W. Power used by these ports beyond a certain point must reduce the power that can be provided to the host.

 

[joevt]

iMac 2012 has Thunderbolt 1 ports. You might be limited to 4K 30Hz or 2560×1600 60Hz.

On a newer Intel Mac, the AGDCDiagnose command can get info about DisplayPort adapters such as the version of DisplayPort.

I made a utility called AllRez which should work with other Macs to do the same thing. It’s still a work in progress.

 https://forums.macrumors.com/threads/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.2309750/post-30760662

 

[joevt]

The description says it has E-mark IC which is the electronic marker that describes the capabilities of the cable. The cable supports USB 3.x and DisplayPort signals just like a Thunderbolt 4 cable so I guess it may be passive in that regard, or if it’s active, then being active doesn’t interfere with the ability to transport USB 3.x and DisplayPort signals. Active Thunderbolt 3 cables, on the other hand, would prohibit USB 3.x and DisplayPort connections.

[joevt]

AW3dclub is referring to the electronic marker inside the cable.

I don’t know if Thunderbolt 4 cables use electronic marker identifiers that differ from USB4. It seems to me that identifying the cable as Thunderbolt 4 is not as useful as identifying the supported modes, maximum bandwidth, and maximum voltage and current.

The USB spec is freely available. Thunderbolt not so.

[joevt]

Not yet. https://insights.club-3d.com/thread/hdmi-2-1-to-usb-c-displayport-1-4-alt-mode/

I haven’t seen the CAC-1333 before. It seems the same as CAC-1332 but does not include USB. I guess that’s good if you don’t have a USB port to provide the power for the adapter but it’s not good if you want to use USB features of the display through the USB-C connection.

 

[joevt]

There’s also the CAC-1332 which is a HDMI 2.0 to USB-C (includes USB 2.0).

You can also maybe install Boot Camp drivers for the LG UltraFine 5K.
https://github.com/timsutton/brigadier

 

[joevt]

Which LG UltraFIne 5K display do you have? Only the newer model 27MD5KL will work with a non-Thunderbolt input. Note that the display is limited to 4K60 or maybe 5K39 when Thunderbolt is not used.

I would try a solution that includes USB so you can use the USB features of the display (audio, camera, USB ports, brightness control) such as the Belkin Charge and Sync cable.
https://egpu.io/forums/gpu-monitor-peripherals/does-a-usb-c-monitor-support-displayport-input-over-a-usb-c-to-displayport-cable/paged/4/#post-79127

 

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