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Roope
Paper Tape
Posts: 7
Registered: ‎01-23-2020
Location: FI
Views: 267
Message 1 of 10

Problems with external monitor (stuck at 30Hz) X1/Gen2 USB-c/U28R55

Hello! 

 

Im having problems with an external monitor. Its stuck at 4k@30Hz, even though my hardware should be able to produce 4k@60Hz. 

 

My setup is 7th gen X1 carbon (20QE001FMX) and USB-C Gen 2 Dock https://support.lenovo.com/us/en/solutions/acc500106 (40AS) and Samsung U28R55.  

 

X1 is connected to the dock and dock to monitor with HDMI 2.0. Ive gone through all the solutions online and Im out of ideas. 

 

Is there something Im missing? HDMI cable is 2.0, monitor supports 4k@60Hz and has HDMI 2.0 port, dock supports one external monitor with 4k@60Hz. 

 

 

 

 

Sw1f7
Paper Tape
Posts: 5
Registered: ‎01-14-2020
Location: ZA
Views: 255
Message 2 of 10

Re: Problems with external monitor (stuck at 30Hz) X1/Gen2 USB-c/U28R55

Hi Roope,

Have a look at the following article:
https://support.lenovo.com/za/en/solutions/pd029622#USB-C%20dock%20Gen%202

I have the same issue, apparently the USB-C Dock Gen 2 does not support 4K @ 60Hz with DP 1.2 systems
Roope
Paper Tape
Posts: 7
Registered: ‎01-23-2020
Location: FI
Views: 243
Message 3 of 10

Re: Problems with external monitor (stuck at 30Hz) X1/Gen2 USB-c/U28R55

Thanks for the reply,

 

Ive looked at that page many times, but never realized that. I just assumed that 1.2 will always support 4k @ 60Hz.  

 

Any idea whats the easiest way to use a 4k@60Hz external monitor with X1? Thunderbolt to DP converter or something?

Sw1f7
Paper Tape
Posts: 5
Registered: ‎01-14-2020
Location: ZA
Views: 225
Message 4 of 10

Re: Problems with external monitor (stuck at 30Hz) X1/Gen2 USB-c/U28R55

Pleasure,

I am not sure, please have a look at the following article:
https://www.reddit.com/r/thinkpad/wiki/newdocks
Sw1f7
Paper Tape
Posts: 5
Registered: ‎01-14-2020
Location: ZA
Views: 222
Message 5 of 10

Re: Problems with external monitor (stuck at 30Hz) X1/Gen2 USB-c/U28R55

Roope
Paper Tape
Posts: 7
Registered: ‎01-23-2020
Location: FI
Views: 215
Message 6 of 10

Re: Problems with external monitor (stuck at 30Hz) X1/Gen2 USB-c/U28R55

Thanks a lot. This clears everything up.

I do feel kinda stupid, but it seems that I'm not the only one who fell for this trap. The advertising for Gen 2 dock is in my mind super misleading. They should add that gen 2 dock doesn't support 4k@60Hz on most lenovo computers.

I just ordered this:
https://www.verkkokauppa.com/fi/product/60728/jhchb/Fuj-tech-USB-C-DisplayPort-kaapeli-2-m?list=OZCY...

You've been really helpful, thanks again!
Sw1f7
Paper Tape
Posts: 5
Registered: ‎01-14-2020
Location: ZA
Views: 203
Message 7 of 10

Re: Problems with external monitor (stuck at 30Hz) X1/Gen2 USB-c/U28R55

Pleasure 😁

I was mislead by the information on the Lenovo USB-C Dock Gen 2 product page as well, there is no way to know that the dock will only support 4K @ 30Hz on 40 of the 43 laptops listed as being compatible with it. Hopefully Lenovo will add the correct information soon.
Roope
Paper Tape
Posts: 7
Registered: ‎01-23-2020
Location: FI
Views: 185
Message 8 of 10

Re: Problems with external monitor (stuck at 30Hz) X1/Gen2 USB-c/U28R55

Hope so! I guess the only dock that can do the trick is the Thunderbolt 3 Gen 2 (40AN)? Luckily I should be able to return the USBC Gen 2 and my employer will get their money back.
Sw1f7
Paper Tape
Posts: 5
Registered: ‎01-14-2020
Location: ZA
Views: 141
Message 9 of 10

Re: Problems with external monitor (stuck at 30Hz) X1/Gen2 USB-c/U28R55

The ThinkPad Pro Docking Station (40AH) and the
ThinkPad Ultra Docking Station (40AJ) should also support 4K @ 60Hz. Maybe someone who have tried it can confirm?

Please let me know how the USB-C to DisplayPort cable works out?
Roope
Paper Tape
Posts: 7
Registered: ‎01-23-2020
Location: FI
Views: 127
Message 10 of 10

Re: Problems with external monitor (stuck at 30Hz) X1/Gen2 USB-c/U28R55

I talked to my coworkers about this and at least in our company there's been tons of confusion concerning these docks.

The best option for some reason is to buy the Hybrid dock (40AF). It supports 2 x 4k@60Hz and is basically the same price as 40AS. I have absolutely no idea why an older model with similar price is so much better?

Ill keep you posted when I get that cable as well.

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