hp elitebook 840 g5 4k 60Hz

[drusklo]

I have a hp elitebook 840 g5 laptop, and I got a 4k external monitor connected through the thunderbolt port, it is a usb-c to usb-c connection. And for whatever reason I am not able to raise the refresh rate above 30Hz. Is there any way to configure it to 60Hz ? Do I need to change something in the BIOS?

Many thanks!

[banhien]

@drusklo 

My machine is also an HP 840 G5. Page 1 of its manual says

Both UMA and discrete configurations support three independent displays through docking stations as follows:

• HP Docking Station - maximum resolution = 2.5K @60Hz (DisplayPort 1) and 2.5K @60Hz (DisplayPort 2)
• HP Thunderbolt 3 Dock - maximum resolution = 4K @60Hz (DP1) and 4K @60Hz (DisplayPort 2)
• HP Thunderbolt Dock 120W or 230W G2 - maximum resolution = 4K @60Hz (DisplayPort 1) and 4K @60Hz (DisplayPort 2) with Thunderbolt

I've got a feeling we need a Thunderbolt dock. I do not have a Thunderbolt to test my HP USB-C G5 dock (first option above) only gives the above result (in cyan).

Regards.