2 x 4K Monitor @ 60 Hz with Thunderbolt Dock G2 Output

[deemehta]

Hi there, 

I have just purchased a Thunderbolt Dock G2 to use with a HP EliteBook 840 G5 that I have from work. Connected to the dock currently are 2 x Asus VP28UQG that support 4K @ 60Hz over DisplayPort 1.2.

Currently the monitors are working fine at 30Hz, but not at 60Hz

According to the Dispplay Capabilities Guide (http://www8.hp.com/h20195/v2/GetPDF.aspx/4AA7-3384ENW.pdf), the supported configuration is for 2 x 4K @ 60Hz is either : 

1 DP + 1 TB port

or 
1 USB Type-C™ Alt mode port + 1 TB port

Does this mean I need to get something like one of these products to get both monitors to show at 60Hz?

Thunderbolt 3.0 to DisplayPort adapter: https://www.amazon.co.uk/dp/B01EPU7R4M/

UCB-C to DisplayPort Cable: https://www.amazon.co.uk/dp/B075V27G2R/

[soccer_dan · Accepted solution]

you are correct... the DP 1.2 hub in the dock that support both DP ports does not have the bandwidth to run 2 4k monitors at 60HZ... you need to obtain an USB-C to DP or HDMI adapter to get the 2nd monitor to also run at 60HZ... the first monitor would be connected to one of the DO connectors

HP sells a USB-C to DP or HDMI adapter that is tested and fully supported

[deemehta]

Thanks Soccer_dan,

I went and got the USB-C to DP adapter (https://www.amazon.co.uk/dp/B01EPU7R4M/) and it work a treat!

[mjs122]

Did you have to make some configuration changes to get this to work? I have a monitor connected to a display port, and another connected to the USB-C port. The display port gets to 4K @ 60 Hz, but the USB-C monitor only displays up to 1080p at 60Hz.

[soccer_dan]

only one of the usb-c ports will support a usb-c to dp or hdmi adapter and 4k resolution... make sure you use a quality adapter and connect it to the appropriate port

[mjs122]

I’m using 2 HP Z27 4K monitors. One is connected to the dock directly to the DP using a DP TO DP cable. The other is connected to the USB-C display port alternative using a USB-C to USB-C cable. Both cables were packaged with the HP monitors.

[soccer_dan]

please, use a usb-c to DP or HDMI adapter to get the 4k/60Hz resolution you need... i am not sure you can do that with usb-c to usb-c cable 

[mjs122]

Oh, you meant Thunderbolt USB-C to DP adapter, and connect it to the Thunderbolt port on the dock and DP on the monitor.

[soccer_dan]

sorry i wasn't clear enough

1st monitor connects to dock via dpdp cable on a DP port

2nd monitor connects to dock's usb-c port via usb-c to dp or hdmi adapter , then a dp or hdmi cable to monitor