Cable help. M1 Pro, Caldigit TS4 & 2 Studio Displays.

[RPhoto]

Hey all, I wonder if someone might be able to help. Mildy long winded but here we go...

I have an M1 Pro MacBook Pro and have had it connected to a Studio Display for a long time, via a TS4. I then have an external drive plugged into the TS4 as well. The idea being I only need one cable to plug into my MacBook Pro to fire everything up. This works but it ties up all the faster TB ports on the dock.

Recently I added a second Studio Display. I would still like to run one cable to the MacBook Pro and have both displays and SSD connect via the TS4. In order to do this I need to connect one of the Studios via the Displayport on the TS4, as the SSD is taking up one of the TB4 ports.

The first USB -> Displayport cable I tried wouldn't power the second Studio Display at all. Black screen. It was a UGREEN DP 1.4 cable rated up to 8k etc. Some research after that suggested the TS4 needs an active bi-directional cable to make full use of the Displayport.

So I ordered the only one I could find on Amazon (UK), which is a (generic, brand I think) VisionTek cable. This cable does work, and I can now plug in one cable to my M1 Pro and both monitors fire up and the SSD connects.

However...if I play full screen 4k video on the Displayport connected screen, it turns off after about 3 minutes. Plus, it has randomly shut off when not even playing video, although only once so far. But I am now not convinced of the cables quality.

Please does anyone know of a reliable USBC to Displayport cable, that will work in my setup? I don't really want to have to plug two cables into the M1 Pro and I'd rather not, just yet, upgrade the dock as I'd need to go TB5 to get the extra USBC port I would need.

Thanks in advance

 

[topgunn]

Don't forget that Thunderbolt bandwidth is limited. One TB4 cable can only carry 40gbps. While that is a lot, a 5k display, like your Studio Display, can use almost 32gbps by itself. I am honestly shocked that having them both connected to the CalDigit works at all. Depending on which M1 MacBook Pro you have (13" or the 14/16") you have either two Thunderbolt Channels or three. Unfortunately, to use both displays to their fullest, you will need to use two thunderbolt ports on your MacBook.

 

[BigBlur]

Yep, need to be mindful of the bandwidth. This dock should support two Studio Displays though, but your other devices connected to the dock could be pushing it over the limit. Try disconnecting some stuff from the dock (or just have only the DisplayPort display plugged in) and see if the display still disconnects. That will tell you if the issue is with the cable or not. To me, it sounds like you're hitting the limit, so then it ends up dropping the display connection.

Instead of plugging the SSD into the dock, are you able to daisy-chain it off the Studio Display? Then use TB for both of the displays. It still may not solve your problem depending on how much bandwidth you're using, but it's worth a shot.

 

[RPhoto]

Don't forget that Thunderbolt bandwidth is limited. One TB4 cable can only carry 40gbps. While that is a lot, a 5k display, like your Studio Display, can use almost 32gbps by itself. I am honestly shocked that having them both connected to the CalDigit works at all. Depending on which M1 MacBook Pro you have (13" or the 14/16") you have either two Thunderbolt Channels or three. Unfortunately, to use both displays to their fullest, you will need to use two thunderbolt ports on your MacBook.

Yep, need to be mindful of the bandwidth. This dock should support two Studio Displays though, but your other devices connected to the dock could be pushing it over the limit. Try disconnecting some stuff from the dock (or just have only the DisplayPort display plugged in) and see if the display still disconnects. That will tell you if the issue is with the cable or not. To me, it sounds like you're hitting the limit, so then it ends up dropping the display connection.

Instead of plugging the SSD into the dock, are you able to daisy-chain it off the Studio Display? Then use TB for both of the displays. It still may not solve your problem depending on how much bandwidth you're using, but it's worth a shot.

Thank you both, that's a very good point. I have the 16" but maybe both displays and the SSD is a little too much. The worry is that the SSD might disconnected rather than a display, in the middle of using Lightroom.

I would plug the SSD in elsewhere but I want to get the maximum possible speed from it and the ports on the display are slower than those on the MBP if I'm not mistaken.

Potentially my safest option is to just plug the second Studio Display direct to the MBP and suck it up that I can't have a reliable one cable solution right now. At some point either an M4 MBP or Studio is on the cards. Just a little reluctant to replace the M1 when it isn't really slowing down my current workflow enough to justify an upgrade...

Thanks again, very helpful!