Mac mini m2 trying to connect dual monitors

[andyx181x]

Hey there group, so I learned the hard way being after buying another monitor that I assumed they can be daisy chained together and the other monitor also has usb C.

Both are LG, the first one is a 27” UN850-W connect to mini via usb c/thunder bolt.

Then I have a 32” UK50T-W that only has 1x DP and 2X HDMI.

I am guessing I can connect the 32 via HDMI but will I be losing out on the maximum resolution/hz going hdmi?

I’m confused between the DP and HDMI which is the better of the two.

Debating maybe cutting my loss and selling the 32”

Any suggestions be helpful, thanks.

 

[joevt]

Both displays are 4K60Hz 10bpc.

HDMI 2.0 can only do 4K60Hz 8bpc 4:4:4. 10bpc would require 4:2:2 or 4:2:0.
You want to use DisplayPort to get 4K60Hz 10bpc RGB.

You can connect two displays to the same Thunderbolt port using a Thunderbolt dock/hub/adapter.
https://eshop.macsales.com/item/OWC/TB3ADP2DPT

 

[andyx181x]

Both displays are 4K60Hz 10bpc.

HDMI 2.0 can only do 4K60Hz 8bpc 4:4:4. 10bpc would require 4:2:2 or 4:2:0.
You want to use DisplayPort to get 4K60Hz 10bpc RGB.

You can connect two displays to the same Thunderbolt port using a Thunderbolt dock/hub/adapter.
https://eshop.macsales.com/item/OWC/TB3ADP2DPT

Thanks for that. So I was able to get the 32” working via HDMI but I do see the difference with the 27” being plugged in via USB C.

So DisplayPort will get me the fullest capability? Would it be better to do HDMI from the Mac mini to a DV connector to the 32”?

The 32” doesn’t have usb C, and I can’t see to get them to daisy chain using DV from both monitors since they are both IN ports.

 

[joevt]

For 4K60, don't use HDMI 2.0. Use DisplayPort for fullest capability.
Use a USB-C to DisplayPort cable if the display doesn't have USB-C.
For macOS, you can only daisy chain a second monitor to a Thunderbolt monitor that is connected to the Mac.
If you want to connect two displays to a single Thunderbolt port, then you need one of Thunderbolt display, Thunderbolt dock, Thunderbolt hub, or Thunderbolt adapter, Thunderbolt device.

- Thunderbolt display: the second display connects to a downstream Thunderbolt port of the display (only works with Thunderbolt displays that have two Thunderbolt ports).
- Thunderbolt hub: connect one display to one USB-C port and connect a second display to another USB-C port of the Thunderbolt hub.
- Thunderbolt adapter: There exist Thunderbolt adapters with two DisplayPort ports. Connect one display to each port.
- Thunderbolt dock/device: Some Thunderbolt docks or devices have a DisplayPort output and a second Thunderbolt port. Connect one display to the DisplayPort port of the Thunderbolt device, and connect a second display to the downstream Thunderbolt port of the Thunderbolt device.

 

[andyx181x]

For 4K60, don't use HDMI 2.0. Use DisplayPort for fullest capability.
Use a USB-C to DisplayPort cable if the display doesn't have USB-C.
For macOS, you can only daisy chain a second monitor to a Thunderbolt monitor that is connected to the Mac.
If you want to connect two displays to a single Thunderbolt port, then you need one of Thunderbolt display, Thunderbolt dock, Thunderbolt hub, or Thunderbolt adapter, Thunderbolt device.

- Thunderbolt display: the second display connects to a downstream Thunderbolt port of the display (only works with Thunderbolt displays that have two Thunderbolt ports).
- Thunderbolt hub: connect one display to one USB-C port and connect a second display to another USB-C port of the Thunderbolt hub.
- Thunderbolt adapter: There exist Thunderbolt adapters with two DisplayPort ports. Connect one display to each port.
- Thunderbolt dock/device: Some Thunderbolt docks or devices have a DisplayPort output and a second Thunderbolt port. Connect one display to the DisplayPort port of the Thunderbolt device, and connect a second display to the downstream Thunderbolt port of the Thunderbolt device.

This is all good details, thanks for sharing.

Since my mini only has 02 usb C ports I don’t want to sacrifice the other one to connect it to the other monitor. Would it still be possible to do a usb C/thunderbolt dock that had a DisplayPort instead?

Should I still let the 27” stay with the usb C connection or switch it to display port as well?

 

[joevt]

Would it still be possible to do a usb C/thunderbolt dock that had a DisplayPort instead?

This is covered by the fourth item in the my list.
Yes, many Thunderbolt docks have have one DisplayPort port. If they have more than one, then probably the other one doesn't work with macOS, unless they sacrificed the downstream Thunderbolt port to create that second DisplayPort output (meaning that the dock has one Thunderbolt port for connecting it to the Mac, and two DisplayPort outputs).
If a Thunderbolt dock or Thunderbolt device has only one DisplayPort port, then you can connect a second display to the downstream Thunderbolt port if it exists using a USB-C cable. Thunderbolt docks/devices usually have one Thunderbolt port for connecting upstream to a Mac and another Thunderbolt port for connecting downstream another Thunderbolt device.
Thunderbolt 4/5 docks may have multiple downstream Thunderbolt ports.

Should I still let the 27” stay with the usb C connection or switch it to display port as well?

USB-C uses DisplayPort, so just leave it.
If the USB-C cable provides USB 3.x support to the display, then you might have reduced DisplayPort bandwidth. Some USB-C displays allow changing the USB speed over USB-C from USB 3.x down to USB 2.0 so that the display can have max DisplayPort bandwidth.
This does not apply to USB-C to DisplayPort cables connected to a DisplayPort port of the display since there's no USB data involved in that connection.

 

[andyx181x]

This is covered by the fourth item in the my list.
Yes, many Thunderbolt docks have have one DisplayPort port. If they have more than one, then probably the other one doesn't work with macOS, unless they sacrificed the downstream Thunderbolt port to create that second DisplayPort output (meaning that the dock has one Thunderbolt port for connecting it to the Mac, and two DisplayPort outputs).
If a Thunderbolt dock or Thunderbolt device has only one DisplayPort port, then you can connect a second display to the downstream Thunderbolt port if it exists using a USB-C cable. Thunderbolt docks/devices usually have one Thunderbolt port for connecting upstream to a Mac and another Thunderbolt port for connecting downstream another Thunderbolt device.
Thunderbolt 4/5 docks may have multiple downstream Thunderbolt ports.


USB-C uses DisplayPort, so just leave it.
If the USB-C cable provides USB 3.x support to the display, then you might have reduced DisplayPort bandwidth. Some USB-C displays allow changing the USB speed over USB-C from USB 3.x down to USB 2.0 so that the display can have max DisplayPort bandwidth.
This does not apply to USB-C to DisplayPort cables connected to a DisplayPort port of the display since there's no USB data involved in that connection.

I can’t believe how little there is out there for thunderbolt docks with displayports. At best they run more than $200. Do you have one to recommend?

 

[joevt]

I can’t believe how little there is out there for thunderbolt docks with displayports. At best they run more than $200. Do you have one to recommend?

They might have USB-C or Mini DisplayPort instead of DisplayPort. Those will be fine. Avoid HDMI.
Yes, Thunderbolt docks are expensive.

CalDigit Element Hub is a Thunderbolt 4 Hub. You can use two of it's USB-C ports for displays. It has one remaining downstream Thunderbolt 4 and for 10 Gbps USB-A ports.
OWC Thunderbolt Hub is less expensive but only has one USB-A port.

Take a look at the list of products at https://www.thunderbolttechnology.n...s_value_many_to_one=All&field_company_nid=All
You want Thunderbolt 3/4/5 not 1/2.

 

[Adora]

This is covered by the fourth item in the my list.
Yes, many Thunderbolt docks have have one DisplayPort port. If they have more than one, then probably the other one doesn't work with macOS, unless they sacrificed the downstream Thunderbolt port to create that second DisplayPort output (meaning that the dock has one Thunderbolt port for connecting it to the Mac, and two DisplayPort outputs).
If a Thunderbolt dock or Thunderbolt device has only one DisplayPort port, then you can connect a second display to the downstream Thunderbolt port if it exists using a USB-C cable. Thunderbolt docks/devices usually have one Thunderbolt port for connecting upstream to a Mac and another Thunderbolt port for connecting downstream another Thunderbolt device.
Thunderbolt 4/5 docks may have multiple downstream Thunderbolt ports.


USB-C uses DisplayPort, so just leave it.
If the USB-C cable provides USB 3.x support to the display, then you might have reduced DisplayPort bandwidth. Some USB-C displays allow changing the USB speed over USB-C from USB 3.x down to USB 2.0 so that the display can have max DisplayPort bandwidth.
This does not apply to USB-C to DisplayPort cables connected to a DisplayPort port of the display since there's no USB data involved in that connection.

Is it normal that USB-C connections only work with a Thunderbolt port on the Mac or Dock side, while the display doesn't even have a Thunderbolt port? At least this is the case on my M3 iMac. Didn't try it on the new mini yet.

I read the USB-C connection mimics DisplayPort 1.2, at least for my display. Is this an emulation or is it just the new miniDisplayPort?

I am using the real DisplayPort cable that is version 1.4 on my display and dock and don't notice any difference.

But the display also has two HDMI ports. 2.0 and 2.1. Only the 2.1 port or the other connections mentioned before support higher refresh rates than 60Hz.

I don't really understand the difference between als those connections.

I would like to buy the same display again as a second one. I also have the problem, that I can't use the same connection type for both. Should I better use HDMI 2.1 or DP 1.2 over USB-C to TB then for the new one, if the other one is also DisplayPort?

The Display is an HP Omen 27K UHD. So not even real 4K.

I never had a Mac with more than one extra Display before, because the iMac had it's own one.

I installed this BetterDisplay app because with some resolutions I could change the brightness. Since then I do understand even less. There are so much settings and this DDC it always wants me to configure. But it isn't full supported, when I activate it. And I sometimes have strange flickering then.

 

[joevt]

Is it normal that USB-C connections only work with a Thunderbolt port on the Mac or Dock side, while the display doesn't even have a Thunderbolt port? At least this is the case on my M3 iMac. Didn't try it on the new mini yet.

Not sure what you mean.
A display has a VGA or DVI or HDMI or DisplayPort or USB-C or Thunderbolt input.
A Mac or dock has a VGA or DVI or HDMI or DisplayPort or USB-C or Thunderbolt output.
You connect an output from the Mac or dock to an input of the display using the appropriate cable or adapter.

Only USB-C outputs and inputs that support USB-C DisplayPort Alt Mode can be used for video.

Some Thunderbolt inputs (such as old Thunderbolt displays) do not accept USB-C DisplayPort Alt Mode input. They require Thunderbolt input.

A Thunderbolt output port can output Thunderbolt or USB-C DisplayPort Alt Mode depending on what is connected.

I read the USB-C connection mimics DisplayPort 1.2, at least for my display. Is this an emulation or is it just the new miniDisplayPort?

Apple Silicon Macs all support DisplayPort 1.4 output using USB-C DisplayPort Alt Mode or Thunderbolt.

4K60 displays and smaller displays don't require more than DisplayPort 1.4 so they usually just support DisplayPort 1.2.

Some adapters or cables are limited to DisplayPort 1.2 link rates.

Some Thunderbolt outputs (older Macs) are limited to DisplayPort 1.2.

Some displays that support DisplayPort 1.4 have an option to limit input to DisplayPort 1.2 for compatibility reasons (if you have an output that doesn't know what to do with DisplayPort 1.4 or doesn't work correctly with DisplayPort 1.4 or if you want to limit the bandwidth the display uses - in case you want to use another display connected to the same MST hub (PC only) or Thunderbolt dock).

I am using the real DisplayPort cable that is version 1.4 on my display and dock and don't notice any difference.

There is no physical difference between a DisplayPort 1.4 cable and a DisplayPort 1.2 cable except that the DisplayPort 1.4 cable is better quality and therefore can transmit bits on each of its 4 lines at 8.1 Gbps.

If your display is set to DisplayPort 1.2, then the cable is transmitting only 5.4 Gbps per line.

DisplayPort 1.2 is enough for 4K60 10bpc RGB.

But the display also has two HDMI ports. 2.0 and 2.1. Only the 2.1 port or the other connections mentioned before support higher refresh rates than 60Hz.

HDMI 2.0 can only do 4K60 8bpc RGB/4:4:4. 4K60 10bpc requires 4:2:2 or 4:2:0.

I don't really understand the difference between als those connections.

DisplayPort has different speeds. HBR, HBR2, HBR3, etc.
https://en.wikipedia.org/wiki/DisplayPort
HDMI has different speeds also.
https://en.wikipedia.org/wiki/HDMI

I also have the problem, that I can't use the same connection type for both.

Why not? Apple tech specs says you can connect two displays via Thunderbolt.
https://support.apple.com/en-ca/111837

Should I better use HDMI 2.1 or DP 1.2 over USB-C to TB then for the new one, if the other one is also DisplayPort?

The Display is an HP Omen 27K UHD. So not even real 4K.

Does your Mac mini have M2 chip or does it have M2 Pro?
M2 chip is limited to HDMI 2.0.
M2 Pro supports HDMI 2.1 so it might be best for the HP Omen 27K UHD which is a 4K144Hz display.

 

[andyx181x]

They might have USB-C or Mini DisplayPort instead of DisplayPort. Those will be fine. Avoid HDMI.
Yes, Thunderbolt docks are expensive.

CalDigit Element Hub is a Thunderbolt 4 Hub. You can use two of it's USB-C ports for displays. It has one remaining downstream Thunderbolt 4 and for 10 Gbps USB-A ports.
OWC Thunderbolt Hub is less expensive but only has one USB-A port.

Take a look at the list of products at https://www.thunderbolttechnology.n...s_value_many_to_one=All&field_company_nid=All
You want Thunderbolt 3/4/5 not 1/2.

Ok so if I go with a thunderbolt hub that only has thunderbolt ports to connect the monitor then should I use a thunderbolt to DisplayPort cable?

My 32” monitor only has one DisplayPort and two hdmi and per this thread DisplayPort is the way to go correct?

 

[Adora]

Thank you for that much information and sorry my first paragraph got a little too long. 🙈

Not sure what you mean.
A display has a VGA or DVI or HDMI or DisplayPort or USB-C or Thunderbolt input.
A Mac or dock has a VGA or DVI or HDMI or DisplayPort or USB-C or Thunderbolt output.
You connect an output from the Mac or dock to an input of the display using the appropriate cable or adapter.

Only USB-C outputs and inputs that support USB-C DisplayPort Alt Mode can be used for video.

Some Thunderbolt inputs (such as old Thunderbolt displays) do not accept USB-C DisplayPort Alt Mode input. They require Thunderbolt input.

A Thunderbolt output port can output Thunderbolt or USB-C DisplayPort Alt Mode depending on what is connected.

My Display has those ports:

So it has 4 connection ports and three cables were included USB-C labeled full featured (whatever that means), DiplayPort 1.4 and HDMI 2.1 and this USB-B (Why is that even used, I know it only from printers, except the micro and mini ones) on display side to USB-A cable for KVM Data. I already learned it has something to do with using the same display on more than one device.

Also strange, the two USB 3.2 Hub ports are USB A. It's a gaming display. I think it's just for charging controllers with more power. I have two 8TB Gaming HDDs for Backups, they also both have USB-A port as a HUB for charging controllers and those are only USB 2.0 with 5W I think, because they only use 3.0 with those strange flat USB-B ports. I got faster USB 3.2 Gen. 2 cables with such a port, but that didn't change anything.

I don't even play games... But the price was good.

So I could use DiplayPort and USB-C and have the same connection for both if I buy a second one?

But the strange thing is it has no Thunderbolt output and it is only recognized on a Thunderbolt port on both Macs (I tested the new one too) and also on my two TB4 Docks it only worked with the TB port. Not a single USB-C port accepted the cable neither on the Macs directly nor on both Docks. I just wondered why and it annoyed me on the iMac because it only had two Thunderbolt ports and the better one needed both ports at once.

I even tried two other cables a USB 3.2 Gen. 2 one and a TB4 one and only the TB4 cable worked but not as good as the one that came with the Display.

It would be nice to have a measure device where you could put in cables and it shows you everything it supports. I have so much different USB-C cables... And they are often labeled wrong when sold, some manufacturers don't even get that not all USB 3.1 and 3.2 hubs support 10 Gbit/s and label also the packaging wrong. I doubt they the other cable details a correct too, very often.

I have TB3 cables that only support 20Gbps that are 0.5m and 1.5m and TB3 or 4 cables that are 2m long and support 40Gbps. But there I know at least the reason for it and I the slower ones were labeled correctly. But myself and some manufactures also confuse TB3 and TB4. I still don't know the difference. Is it only the USB 4.0 support? Those are really rare to find and there are also two different speed versions.

Even more bad is, when ports are labeled wrong.

Maybe something like this cable measuring device even exists already. I have to look on Amazon.

If the display would be Thunderbolt too I should see it here somewhere like every other TB device. Or does that not happen when it's used as Display port? But why wouldn't they mention that the port on the display is Thunderbolt. The price also was too cheap. It can't really be.

Apple Silicon Macs all support DisplayPort 1.4 output using USB-C DisplayPort Alt Mode or Thunderbolt.

4K60 displays and smaller displays don't require more than DisplayPort 1.4 so they usually just support DisplayPort 1.2.

Some adapters or cables are limited to DisplayPort 1.2 link rates.

Some Thunderbolt outputs (older Macs) are limited to DisplayPort 1.2.

Some displays that support DisplayPort 1.4 have an option to limit input to DisplayPort 1.2 for compatibility reasons (if you have an output that doesn't know what to do with DisplayPort 1.4 or doesn't work correctly with DisplayPort 1.4 or if you want to limit the bandwidth the display uses - in case you want to use another display connected to the same MST hub (PC only) or Thunderbolt dock).


There is no physical difference between a DisplayPort 1.4 cable and a DisplayPort 1.2 cable except that the DisplayPort 1.4 cable is better quality and therefore can transmit bits on each of its 4 lines at 8.1 Gbps.

If your display is set to DisplayPort 1.2, then the cable is transmitting only 5.4 Gbps per line.

DisplayPort 1.2 is enough for 4K60 10bpc RGB.

I could change the DisplayPort mode for USB-C to 1.4 too. There is a menu were you can chose everything from 1.0 to 1.4 for both ports, so the DisplayPort too. Maybe the info was outdated.

HDMI 2.0 can only do 4K60 8bpc RGB/4:4:4. 4K60 10bpc requires 4:2:2 or 4:2:0.


DisplayPort has different speeds. HBR, HBR2, HBR3, etc.
https://en.wikipedia.org/wiki/DisplayPort
HDMI has different speeds also.
https://en.wikipedia.org/wiki/HDMI


Why not? Apple tech specs says you can connect two displays via Thunderbolt.
https://support.apple.com/en-ca/111837


Does your Mac mini have M2 chip or does it have M2 Pro?
M2 chip is limited to HDMI 2.0.
M2 Pro supports HDMI 2.1 so it might be best for the HP Omen 27K UHD which is a 4K144Hz display.

I even have an M4 Pro and just tried HDMI again. Something was wrong with DP and the display brightness didn't work anymore. The backlight was on, but it stayed black.

Somehow it came back and it seems I messed too much with the settings and activated KVM somehow. There is a button on the back next to the menu button. Suddenly the display was twice in system settings. Normally even if I use three connections, DP, USB-C and HDMI that doesn't happen, it just chooses one connection automatically or I had to do it manually in the menu of the display. It can be disabled to choose the connection automatically.

 

[joevt]

Ok so if I go with a thunderbolt hub that only has thunderbolt ports to connect the monitor then should I use a thunderbolt to DisplayPort cable?

My 32” monitor only has one DisplayPort and two hdmi and per this thread DisplayPort is the way to go correct?

USB-C to DisplayPort 1.2 cable is good enough for 4K60.

USB-C to DisplayPort 1.4 cable for higher resolutions and refresh rates. Backwards compatible with DisplayPort 1.2.

USB-C to DisplayPort 2.1 cable should also work. Probably only useful for Thunderbolt 5 Macs and Thunderbolt 5 hubs/docks. It should work with DisplayPort 1.2 and 1.4 sources (backwards compatible). It should be better quality than DisplayPort 1.2 or 1.4 cables.

My Display has those ports:

So it has 4 connection ports and three cables were included USB-C labeled full featured (whatever that means), DiplayPort 1.4 and HDMI 2.1

What display do you have?

Some USB-C ports or cables are only for charging (they might support USB 2.0 but that's all).

USB-C full featured means it does video and data and power. DisplayPort 1.4 means the USB-C cable should be at least 10 Gbps (USB 3.1 gen 2) or 20 Gbps (USB 3.1 gen 2x2) which are actually the same (USB 3.1 just uses one lane while USB 3.2 x2 uses two lanes).

The USB-C input of the display probably allows DisplayPort 1.4 and one lane of USB 3.x. USB 3.x uses two of the four super speed lines of the USB-C cable, leaving only 2 for DisplayPort 1.4. 2 lanes of DisplayPort 1.4 allows for 4K60 8bpc without DSC. Some displays have a switch in the menu to allow 4 lanes of DisplayPort over USB-C which limits USB speeds to USB 2.0 which is good enough for mouse/keyboard.

Your display probably supports DSC so you should be ok with 2 lanes of DisplayPort 1.4 up to 4K120.

and this USB-B (Why is that even used, I know it only from printers, except the micro and mini ones) on display side to USB-A cable for KVM Data. I already learned it has something to do with using the same display on more than one device.

Also strange, the two USB 3.2 Hub ports are USB A. It's a gaming display. I think it's just for charging controllers with more power.

Your display has USB-A ports which you can connect a keyboard and mouse.

KVM stands for keyboard, video, mouse. A KVM switch lets you switch the keyboard, video, and mouse between two computers. It requires a video and USB inputs from each computer. USB-C is used for USB from one computer and can also be used for video from the same computer. USB-B is used for USB from the other computer. One of the HDMI or DisplayPort ports must be used for video from that other computer.

I have two 8TB Gaming HDDs for Backups, they also both have USB-A port as a HUB for charging controllers and those are only USB 2.0 with 5W I think, because they only use 3.0 with those strange flat USB-B ports. I got faster USB 3.2 Gen. 2 cables with such a port, but that didn't change anything.

The USB-B port (Standard B) of your display is compatible with USB 2.0 USB-B and USB 3.x USB-B.
The flat USB-B ports (Micro B) is compatible with USB 2.0 Micro B and USB 3.x Micro B.
https://en.wikipedia.org/wiki/USB

So I could use DiplayPort and USB-C and have the same connection for both if I buy a second one?

True. They would both be DisplayPort 1.4. However, you would need to switch the USB-C port to 4 lanes of DisplayPort + USB 2.0 instead of 2 lanes of DisplayPort + USB 3.x to make them exactly the same.

But the strange thing is it has no Thunderbolt output

Yes, non Thunderbolt displays don't have Thunderbolt outputs because they have no Thunderbolt inputs. Why would it have a Thunderbolt output?

and it is only recognized on a Thunderbolt port on both Macs (I tested the new one too) and also on my two TB4 Docks it only worked with the TB port. Not a single USB-C port accepted the cable neither on the Macs directly nor on both Docks.

Only USB-C ports with USB-C DisplayPort Alt Mode capability will output video. Thunderbolt ports support USB-C DisplayPort Alt Mode. Some Macs have USB-C (non-Thunderbolt) ports that don't support USB-C DisplayPort Alt Mode. Some docks may have USB-C ports that don't support USB-C DisplayPort Alt Mode.
https://en.wikipedia.org/wiki/USB-C

The HP Thunderbolt Dock G2 is an example of a dock with a USB-C port that supports USB-C DisplayPort Alt Mode. It also has USB-C ports that don't support USB-C DisplayPort Alt Mode.

What Macs / docks do you have that have USB-C ports that are not Thunderbolt ports?

I just wondered why and it annoyed me on the iMac because it only had two Thunderbolt ports and the better one needed both ports at once.

better one what?
You can add more Thunderbolt ports using a Thunderbolt 4/5 hub/dock.

I even tried two other cables a USB 3.2 Gen. 2 one and a TB4 one and only the TB4 cable worked but not as good as the one that came with the Display.

A USB 3.2 Gen 2 USB-C cable should be sufficient for the USB-C DisplayPort Alt Mode input of a DisplayPort 1.4 display.
Why would you not use the cable that comes with the display? What are you trying to achieve/improve by switching cables?
If the display is not TB4 that you don't need to waste a TB4 cable on it.

It would be nice to have a measure device where you could put in cables and it shows you everything it supports. I have so much different USB-C cables... And they are often labeled wrong when sold, some manufacturers don't even get that not all USB 3.1 and 3.2 hubs support 10 Gbit/s and label also the packaging wrong. I doubt they the other cable details a correct too, very often.

I can connect a USB-C cable to a USB-C NVMe SSD to determine if it supports gen 2 speed (10 Gbps which also implies gen 2x2 20 Gbps), or gen 1 speed (5 Gbps which implies gen 1x2 speed 10 Gbps) or USB 2.0 speed (basically a cable that is only good for charging).

I have TB3 cables that only support 20Gbps that are 0.5m

That seems like a broken cable - no better than a USB 3.1 gen 2 cable (which can work fine for Thunderbolt at 20 Gbps). Did you test it on an Intel Mac's Thunderbolt port?

and 1.5m and TB3 or 4 cables that are 2m long and support 40Gbps. But there I know at least the reason for it and I the slower ones were labeled correctly. But myself and some manufactures also confuse TB3 and TB4. I still don't know the difference. Is it only the USB 4.0 support? Those are really rare to find and there are also two different speed versions.

TB4 cables may be backward compatible with USB 3.x while TB3 cables are not? I forget all the details.

If the display would be Thunderbolt too I should see it here somewhere like every other TB device. Or does that not happen when it's used as Display port? But why wouldn't they mention that the port on the display is Thunderbolt. The price also was too cheap. It can't really be.

If the display is not advertised as a Thunderbolt display, then it's probably not a Thunderbolt Display. It's just a USB-C DisplayPort Alt Mode display.

I could change the DisplayPort mode for USB-C to 1.4 too. There is a menu were you can chose everything from 1.0 to 1.4 for both ports, so the DisplayPort too. Maybe the info was outdated.

Leave it at 1.4 unless there's a compatibility problem with a really old computer or something.

I even have an M4 Pro and just tried HDMI again. Something was wrong with DP and the display brightness didn't work anymore. The backlight was on, but it stayed black.

Somehow it came back and it seems I messed too much with the settings and activated KVM somehow. There is a button on the back next to the menu button. Suddenly the display was twice in system settings. Normally even if I use three connections, DP, USB-C and HDMI that doesn't happen, it just chooses one connection automatically or I had to do it manually in the menu of the display. It can be disabled to choose the connection automatically.

You shouldn't connect more than one output from the same Mac to a display unless you're doing some experiments.

 

[Adora]

@joevt Thanks for the great explanation. Could take a while to answer everything. I'll try it after I slept.

 

[andyx181x]

USB-C to DisplayPort 1.2 cable is good enough for 4K60.

USB-C to DisplayPort 1.4 cable for higher resolutions and refresh rates. Backwards compatible with DisplayPort 1.2.

USB-C to DisplayPort 2.1 cable should also work. Probably only useful for Thunderbolt 5 Macs and Thunderbolt 5 hubs/docks. It should work with DisplayPort 1.2 and 1.4 sources (backwards compatible). It should be better quality than DisplayPort 1.2 or 1.4 cables.


What display do you have?

Some USB-C ports or cables are only for charging (they might support USB 2.0 but that's all).

USB-C full featured means it does video and data and power. DisplayPort 1.4 means the USB-C cable should be at least 10 Gbps (USB 3.1 gen 2) or 20 Gbps (USB 3.1 gen 2x2) which are actually the same (USB 3.1 just uses one lane while USB 3.2 x2 uses two lanes).

The USB-C input of the display probably allows DisplayPort 1.4 and one lane of USB 3.x. USB 3.x uses two of the four super speed lines of the USB-C cable, leaving only 2 for DisplayPort 1.4. 2 lanes of DisplayPort 1.4 allows for 4K60 8bpc without DSC. Some displays have a switch in the menu to allow 4 lanes of DisplayPort over USB-C which limits USB speeds to USB 2.0 which is good enough for mouse/keyboard.

Your display probably supports DSC so you should be ok with 2 lanes of DisplayPort 1.4 up to 4K120.


Your display has USB-A ports which you can connect a keyboard and mouse.

KVM stands for keyboard, video, mouse. A KVM switch lets you switch the keyboard, video, and mouse between two computers. It requires a video and USB inputs from each computer. USB-C is used for USB from one computer and can also be used for video from the same computer. USB-B is used for USB from the other computer. One of the HDMI or DisplayPort ports must be used for video from that other computer.


The USB-B port (Standard B) of your display is compatible with USB 2.0 USB-B and USB 3.x USB-B.
The flat USB-B ports (Micro B) is compatible with USB 2.0 Micro B and USB 3.x Micro B.
https://en.wikipedia.org/wiki/USB


True. They would both be DisplayPort 1.4. However, you would need to switch the USB-C port to 4 lanes of DisplayPort + USB 2.0 instead of 2 lanes of DisplayPort + USB 3.x to make them exactly the same.


Yes, non Thunderbolt displays don't have Thunderbolt outputs because they have no Thunderbolt inputs. Why would it have a Thunderbolt output?


Only USB-C ports with USB-C DisplayPort Alt Mode capability will output video. Thunderbolt ports support USB-C DisplayPort Alt Mode. Some Macs have USB-C (non-Thunderbolt) ports that don't support USB-C DisplayPort Alt Mode. Some docks may have USB-C ports that don't support USB-C DisplayPort Alt Mode.
https://en.wikipedia.org/wiki/USB-C

The HP Thunderbolt Dock G2 is an example of a dock with a USB-C port that supports USB-C DisplayPort Alt Mode. It also has USB-C ports that don't support USB-C DisplayPort Alt Mode.

What Macs / docks do you have that have USB-C ports that are not Thunderbolt ports?


better one what?
You can add more Thunderbolt ports using a Thunderbolt 4/5 hub/dock.


A USB 3.2 Gen 2 USB-C cable should be sufficient for the USB-C DisplayPort Alt Mode input of a DisplayPort 1.4 display.
Why would you not use the cable that comes with the display? What are you trying to achieve/improve by switching cables?
If the display is not TB4 that you don't need to waste a TB4 cable on it.


I can connect a USB-C cable to a USB-C NVMe SSD to determine if it supports gen 2 speed (10 Gbps which also implies gen 2x2 20 Gbps), or gen 1 speed (5 Gbps which implies gen 1x2 speed 10 Gbps) or USB 2.0 speed (basically a cable that is only good for charging).


That seems like a broken cable - no better than a USB 3.1 gen 2 cable (which can work fine for Thunderbolt at 20 Gbps). Did you test it on an Intel Mac's Thunderbolt port?


TB4 cables may be backward compatible with USB 3.x while TB3 cables are not? I forget all the details.


If the display is not advertised as a Thunderbolt display, then it's probably not a Thunderbolt Display. It's just a USB-C DisplayPort Alt Mode display.


Leave it at 1.4 unless there's a compatibility problem with a really old computer or something.


You shouldn't connect more than one output from the same Mac to a display unless you're doing some experiments.

Thanks a lot for all your help.

It just occurred to me I have an OWC mini stack stx and it’s also a thunderbolt hub!

All ports are thunderbolt 4 and can support those resolutions and frequency. I just need to get me a thunderbolt to DisplayPort cable and I’m good to go!