Question about USB-C with DisplayPort 1.4 on new motherboards

[TaylorHu]

I've noticed that some (all?) of the new X870E motherboards have USB-C with DP ports on them. Take the ProArt X870E-CREATOR WIFI, for example, it has two. I'm unsure how that works though. Is it still using the video generated by the GPU, or do you need a CPU with an integrated GPU? I'm mostly curious as to how it would work with something like a Huion Pen Display. Most of them have two connection options, either just USB-C to USB-C, usually demonstrated plugged into a laptop, or a USB-C to 3-way dongle (HDMI, 1 USB-A for data, another USB-A for power). 3-way dongle is what I am currently using for my desktop, but I would love it if I could replace that with one USB-C cable instead. Followup, would theoretically any USB-C cable work, or do I need to make sure it supports any specific protocols?

[Agall]

10 minutes ago, TaylorHu said:

I've noticed that some (all?) of the new X870E motherboards have USB-C with DP ports on them. Take the ProArt X870E-CREATOR WIFI, for example, it has two. I'm unsure how that works though. Is it still using the video generated by the GPU, or do you need a CPU with an integrated GPU? I'm mostly curious as to how it would work with something like a Huion Pen Display. Most of them have two connection options, either just USB-C to USB-C, usually demonstrated plugged into a laptop, or a USB-C to 3-way dongle (HDMI, 1 USB-A for data, another USB-A for power). 3-way dongle is what I am currently using for my desktop, but I would love it if I could replace that with one USB-C cable instead. Followup, would theoretically any USB-C cable work, or do I need to make sure it supports any specific protocols?

They're USB-C with DP-alt for the iGPU. That X870E does have the DP-in like previous versions which allows you to use the USB4 port with a dGPU passed through.

 

To demonstrate where this isn't the case, the Pro Art that has DP-in for the type-c to handle passthrough from the dGPU:

 

 

 Amazon.com: ASUS ProArt X570-Creator WiFi AMD X570S Ryzen AM4 ATX Content Creation Motherboard(PCIe 4.0, Passive PCH Cooling, 2xThunderbolt 4 Type-C Ports, 10 Gb & 2.5 Gb LAN, WiFi 6E, 3X M.2 Slots,Creator Hub) : Electronics

 

In this scenario, you'd be able to get display out from the GPU through the USB-C port using that DP-in and the Thunderbolt 4 port.

[Eigenvektor]

2 minutes ago, Agall said:

To demonstrate where this isn't the case, check out this older model of the Pro Art that has DP-in for the type-c to handle passthrough from the dGPU:

https://dlcdnets.asus.com/pub/ASUS/mb/SocketAM5/ProArt_X870E-CREATOR_WIFI/E23930_ProArt_X870E-CREATOR_WIFI_EM_WEB.pdf?model=ProArt X870E-CREATOR WIFI

 

The manual of the one linked by OP says the same (page 48). You need to connect the DP-out of your discrete GPU to the DP-in of the motherboard. Then you can use the USB-C port as a DP out.

[Agall]

Just now, Eigenvektor said:

https://dlcdnets.asus.com/pub/ASUS/mb/SocketAM5/ProArt_X870E-CREATOR_WIFI/E23930_ProArt_X870E-CREATOR_WIFI_EM_WEB.pdf?model=ProArt X870E-CREATOR WIFI

 

The manual of the one linked by OP says the same (page 48). You need to connect the DP-out of your discrete GPU to the DP-in of the motherboard. Then you can use the USB-C port as a DP out.

Yeah, I just noticed that the x870e version of this board also has this feature like previous models. Seems to be standard on the Pro Art series within the last few generations to have a DP-in, on the Intel side too.

[Agall]

15 minutes ago, TaylorHu said:

Followup, would theoretically any USB-C cable work, or do I need to make sure it supports any specific protocols?

USB-C cables get weird since some do only support certain standards. Unfortunately, I don't have any type-c input monitors to test the various type-c cables I have on how this functions, since both my motherboard and my spare 7900 XT have different types of type-c outputs, some being USB without DP-alt and some having DP-alt.

[GuiltySpark_]

On desktops, there are two ways this is integrated. I find it helpful to look at block diagrams. 

 

Either your Type C/Thunderbolt ports are internally routed to iGPU outputs

 

(example: My X670E Taichi)

 

OR

 

You have a DP-in port that will route whatever source you choose out over the Type C/Thunderbolt port. 

 

(example: the ProArt board above)

 

 

[Agall]

36 minutes ago, GuiltySpark_ said:

You have a DP-in port that will route whatever source you choose out over the Type C/Thunderbolt port. 

 

(example: the ProArt board above)

I think it would be really cool if there was a way to do this over PCIe internally rather than externally.

[GuiltySpark_]

1 hour ago, Agall said:

I think it would be really cool if there was a way to do this over PCIe internally rather than externally.

Yeah, i'm not entirely sure why that isn't a feature. 

 

 

[Agall]

38 minutes ago, GuiltySpark_ said:

Yeah, i'm not entirely sure why that isn't a feature. 

 

 

I don't think cards are designed to be able to pass displayout over PCIe, so that might require a special controller, then the motherboard would have to be able to receive that signal as displayport and pass it over type-c like this board doesn externally.

 

Its definitely something I'd pay extra money for to have, even if my monitor doesn't have a type-c input right now. A single cable solution for my monitor to provide USB, DP, and power would be AMAZING. Plenty of monitors fit within a 100W power budget as is, and plenty of motherboards have type-c PD capability, especially with the extra room people generally spec into their power supplies.