[SOLVED] Driving an LG 34WN80C-B using Thunderbolt 4 interface ?

[Penniless Film Maker]

I have just completed an editing/streaming workstation using the following components:

• Intel 11900k
• MSI Z590 Ace
• RTX 3060
• Logitech BRIO webcam
• Elgato Wave 3 microphone

I have not yet purchased a monitor but am considering the LG 34WN80C-B. In reading the manual it appears that I can drive the monitor using the USB-C input connector on the monitor. The Ace provides 2 Thunderbolt-4 ports including mini DP inputs for each. The motherboard also provides a short cable to provide the DP out to the miniDP input on the back of the motherboard.

This suggest that I could hook the output of the 3060 to the input of the TB port and use USB-C to drive the monitor. The monitor would simultaneously act as a USB hub providing 2 USB 3.2 gen 1 ports on the monitor. This would allow me to use those inputs for the microphone and the webcam greatly simplifying my cable management at this station.

Am I delusional? Is it the case that I could drive the 3400 x 1440 monitor and collect the outputs of the microphone and camera using a single cable? This would also free up two USB 3.2 gen 1 inputs at the back of the machine. I actually have a second camera that need a place to hook up.

I did notice that the Ace manual states that it supports TB-4(40Gbit), USB 3.2 gen 2x2(20Gbit), USB 3.2 gen 2(10Gbit). It does not say it supports USB 3.2 gen 1. Surely it could not be true that this mode is not supported? Also the manual for the LG states that it supports USB 2.0 with one connector and USB 3.2 gen 1 with another. Could it be the case that I am that close but no cigar because the Ace does not support gen1 on the TB-4 port?

I am not a gamer. I will do 4k video editing and streaming of PowerPoint presentations using OBS. 60Hz refresh is sufficient for my needs. If this is too much to ask I would like to be disappointed now rather than after I get this monitor. I would still likely purchase this monitor as most others are aimed at gamers.

FYI: My current monitor is a 12 years old Dell that runs at 1080p60. There is no problem with it other than no DP inputs and it will not talk to my BMPCC 4k using HDMI.

 

[maikutech]

I think the usb-c port is meant for media-network storafe devices, if you want to use multiple usb 3.0 /3.1 devices its doable.
https://www.lg.com/us/monitors/lg-34wn80c-b-ultrawide-monitor
But to be very sure of that, please read the recent amazon customer reviews.
https://www.amazon.com/LG-34WN80C-B-inch-Connectivity-Compatibility/dp/B07YGZ7C1K?th=1
It will you what is plausible and what isn't plausible for use with that LG monitor.
I recommend this for a usb hub on TV's game consoles, and monitors, its very power resource friendly.
https://www.amazon.com/gp/product/B00JX1ZS5O/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

 

[Penniless Film Maker]

I think the usb-c port is meant for media-network storafe devices, if you want to use multiple usb 3.0 /3.1 devices its doable.
https://www.lg.com/us/monitors/lg-34wn80c-b-ultrawide-monitor
But to be very sure of that, please read the recent amazon customer reviews.
https://www.amazon.com/LG-34WN80C-B-inch-Connectivity-Compatibility/dp/B07YGZ7C1K?th=1
It will you what is plausible and what isn't plausible for use with that LG monitor.
I recommend this for a usb hub on TV's game consoles, and monitors, its very power resource friendly.
https://www.amazon.com/gp/product/B00JX1ZS5O/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Thank you for the reply. I am not sure I understand. LG seems to include the statement that it has a USB-C input. Sadly, this is a mechanical spec. The same spec is used by USB and Thunderbolt although the cables are not the same. I know that to get full TB-4 performance the cables may be both expensive and short.

It does not answer the question if my TB-4 will talk to their monitor. TB-4 should be backward compatible with whatever the monitor has except USB-2.0. The LG spec does say I can drive one 4k monitor. I know that TB-4 can drive 2 of these so it may be working at USB 3.2x2 rate. The TB should be able to do this. 1 4k monitor is more pixels than this LG monitor has so I should be able to drive it using that port. The spec, which I have as a pdf file and the data on the Amazon site you provide both say that it will simultaneously create a USB hub providing 2 USB ports supporting USB 3.2 gen 1 on Type A connectors. This is great and would greatly ease my cable management problem. If this works I could run one cable rather than three and free up two USB 3.2 gen 1s on the rear panel of the computer. ( Currently the USB-C cable supporting the microphone is flying through the air because it is just barely long enough to reach the computer.)

I do not understand what information I can extract from the CPU-Z image?

 

[maikutech]

Thank you for the reply. I am not sure I understand. LG seems to include the statement that it has a USB-C input. Sadly, this is a mechanical spec. The same spec is used by USB and Thunderbolt although the cables are not the same. I know that to get full TB-4 performance the cables may be both expensive and short.

It does not answer the question if my TB-4 will talk to their monitor. TB-4 should be backward compatible with whatever the monitor has except USB-2.0. The LG spec does say I can drive one 4k monitor. I know that TB-4 can drive 2 of these so it may be working at USB 3.2x2 rate. The TB should be able to do this. 1 4k monitor is more pixels than this LG monitor has so I should be able to drive it using that port. The spec, which I have as a pdf file and the data on the Amazon site you provide both say that it will simultaneously create a USB hub providing 2 USB ports supporting USB 3.2 gen 1 on Type A connectors. This is great and would greatly ease my cable management problem. If this works I could run one cable rather than three and free up two USB 3.2 gen 1s on the rear panel of the computer. ( Currently the USB-C cable supporting the microphone is flying through the air because it is just barely long enough to reach the computer.)

I do not understand what information I can extract from the CPU-Z image?

If you need to know for sure before buying, I suggest you call them and have them verify that.
https://www.lg.com/us/support/telephone

 

[Penniless Film Maker]

After a long conversation with LG Customer Service it is clear to me that they do not know the answer to my question. In their defense it seems that single persons support a broad product line and do not know the details of single products. There were quick and wanted to be helpful but they only quoted content to me that I have already read in the manual.

Conjecture:

The monitor has a USB-C input that has limited capability. It is not a Thunderbolt port. I have two Thunderbolt 4 ports that can drive 2 ,4k displays or a single 8k display. I just want to drive a single 3440x1440 display and get a USB 3.0 hub on the same cable. I think that the monitor will do either of these but not both at the same time. If it would do both I could reduce connections from the system to the my desk from 3 to one cable. If I used USB-C to drive the display I would still need the other two USB cables for my mic and webcam. If I use the USB-C to drive the USB hub in the monitor I still need a DP cable to get an image on the display. It reduced the cable count only by one. I do need USB 3.2 gen 1 speed and if it is not connected correctly one gets USB 2.0 speed. This is not acceptable and constitutes an unnecessary complication just to eliminate one cable.

Moving On:

I will likely purchase the monitor as planned. I will use Display Port to drive the display and separate USB-C cables with adaptors at the Host end which is what I am doing now. I believe this confusion begins with those who wrote the manual who wanted to talk about the capabilities of the monitor without drawing attention to its limitations. I have two Thunderbolt 4 ports and so far I have not found a way to take advantage of their unique capabilities other than as additional USB ports. This is exacerbated by the fact that USB-C is a type of connector. It does not specify what standards are supported. I would like one 3440x1440 display at 60Hz(*) with two USB 3.2 gen 1 ports on the monitor hub. While I understand that the monitor was not designed to support this it is saddening that it has been so difficult to just get an answer from LC or their documentation that the monitor does not provide this.

* I am not a gamer and do not need a refresh faster than 60Hz.