Samsung Screen and XPS 15 - Stuck at 30hz with Dell Dock

[Nozaaa]

Hey

Got a little problem with my laptop (and my screen and my usb dongle) and perhaps someone here will be able to help me !

 

I've got a XPS 15" (XPS 15 9560) with an  NVIDIA GeForce GTX 1050 and Intel® HD Graphics 630 onboard.

I've got also an external screen from Samsung  lu28e590ds wich can do 4k @60hz.

 

Previously i was using a little dongle from Choetech that was doing the Job using the Display Port input on my screen, i was able to have the native resolution / refresh rate.

 

I moved my desktop close to a RJ45 (i needed faster speed than the wifi) and so i bought (my compagny) the Dell dongle wich is advertised to do just what i need : Ethernet + Video 4k@60hz in a relatively nice form factor.

Problem is, i can't have 4k@60Hz no matter what i do.

 

I've tried:

- Display port cable (enabling DisplayPort 1.1 or 1.2 on my screen)

- Hdmi from the laptop itself

- Hdmi from the dongle

- Pluging the Choetech adaptator on the usb-c port on the Dell dongle

 

The only thing i can think of is that the Dell dongle "need PC models (with support for DisplayPort Alt-Mode 1.3 & above standard) when connected to displays that offer 4K résolution at 60Hz." wich is the case of my laptop but my screen support only DisplayPort 1.2. Is it the problem here?

 

Thanks a lot !

(Sorry as English is not my native langage)

Edited September 22, 2020 by Nozaaa
DIsplay port 1.2 instead of 1.3 for my screen