MBP external monitor goes from 60Hz to 30Hz when portrait mode
 

Hi,

I have issues with FPS lowered to 30HZ when choosing my 4k monitor as portrait mode on my MBP.

HW:
MacBook Pro (13-inch, 2017, Four Thunderbolt 3 Ports)
ICY BOX IB-DK2243AC
2 x ASUS MG28UQ
DP cable between ICY BOX and monitors.
USB C between MBP and ICY BOX.

SW:
macOS Mojave 10.14.2
DisplaylinkDriver 5.0

Both monitors is connected using DP.

Running both monitors in landscape mode (3840 x 2160 @ 60Hz) is just fine.
But once I start rotating one of the monitors to achieve portrait mode the refresh rate is lowered.
When in portrait mode (2160 x 3840) the FPS is stuck at 30Hz.
It will not give me 60Hz unless the rotation is set at Standard. Doesn’t matter if 90/180/270 degrees.

Confirmed portrait mode is working fine at 60Hz using a Windows computer connected to my ICY BOX.
Also 60Hz in portrait mode is working flawless when MBP is connected directly to monitor with HDMI.

Was hoping anyone have experienced the same and could provide some tips? If not is this something I was hoping DisplayLink could look into. One thing to mention aswell is when installing the DisplayLink driver 4.0 that was on the CD together with the ICYBox both my external monitors is showing in «Graphic/Monitors» in the MAC system info. But they are not visible anywhere in the MAC`s system info after updating to DisplayLink 5.0.

BR,
Sindre