Question PD3220U Thinderbolt 3 cable

[grgart]

Hello,
I got 2 workstations with 2x4K monitors, from which primary WS needs to have the best quality input as possible. Cable setups are shown at the picture below:

So I wanted to take advantage of PD3220U KWM Switch but as I understood one pc needs to be attached with Thunderbold 3 cable in order to make KWM switch work.
I Just purchased 2m Thunderbold 3 cable (20Gbit) but I can't get same picture properties as with DisplayPort 1.4 cable, it's way lower quality, see the picture below:

Is this limit with 20Gbit Thunderbold 3 cable normal in other words I can't get the same display properties with Thunderbolt 3 as with display port 1.4?
If possible, what type of thunderbolt 3 cable I need to purchase to take advantage of quality input?
Also with HDMI cable I can only get 8bits compared to Display port cable 10bits, is this normal ?

Thank you.

 

[Glenwing]

A 20 Gbit/s cable will only give you DP 1.2 capabilities, but that should still support 4K 60 Hz 10 bpc RGB. Are you unable to change the output color format to RGB?

Yes, 4K 60 Hz 10 bpc RGB exceeds the HDMI spec, so it is normal for 10 bpc color is not supported at 4K 60 Hz RGB over HDMI.

 

[grgart]

A 20 Gbit/s cable will only give you DP 1.2 capabilities, but that should still support 4K 60 Hz 10 bpc RGB. Are you unable to change the output color format to RGB?

Thank you for your answer.
I can't change any settings with Thunderbolt 3 cable. It just sets those settings you see on the screengrab back again.
Maybe the cable is not good enough although it is stated that it supports 20Gbit. I bought it on Aliexpress.

https://www.aliexpress.com/item/32971281023.html?spm=a2g0s.9042311.0.0.33194c4dLQkQ1z

I'll try to borrow other Thunderbolt cable from friends and test it.

Anyway, KWM switch is purely designed giving you an option to use Thunderbolt3 cable for other computer (0.5m provided with monitor) so you can't attach Workstation which is not so close to monitor. It only gives you the option to attach a laptop or something closer than 0.5m to monitor. It would be much more convenient that KWM switch has 2x USB upstream inputs, since its primarily used to switch keyboard/mouse set between workstations.

 

[grgart]

UPDATE:

I just tested my PD3220U Thunderbolt 3 input with 70cm Thunderbolt 3 cable provided with the monitor, which should be 40Gbit cable.

I found that the Workstation GPU does not have full 40Gbit thunderbolt 3 output:
https://www.msi.com/Graphics-card/GeForce-RTX-2080-SEA-HAWK-X/Specification

So I Tested it with the laptop wich suppose to have a full 40Gbit Thunderbolt 3 output (HP Omen 15-dh0014nm).

I can't get full specs picture even with this original cable provided with monitor (see screengrab in the first post).
Display port 1.4 gives full specs.
HDMI 2.0 gives nearly full specs from both the laptop and PC (limited to 8bits).

Any idea why I only get those limited input specs even with a short 70cm cable and TB3 Laptop?

Thank you.