MBP 13 Late 2017 and Anker Hub 555 30Hz on external display

[maddovr]

MBP 13 Late 2017 and Anker Hub 555 30Hz on external display

[waydabber]

Honestly, I am not sure, this seems to be some kind of bandwidth issue. Turning on deep color is not ideal as it needs more bandwidth (10+ bits per color instead of the traditional 8 bits) - to compensate for that, some devices my try to use chroma subsampling but if you see the conneciton as 4:4:4 then that is not happening either, so the system might not have better choice than to revert to a 30Hz mode.

On Apple Silicon you can understand rather easily what color mode, bandwidth etc is selected during display negotiation from the available options from looking at the kernel logs + matching the selected modes with available color modes in the IO registry. On Intel however the easiest way is to use the tool AllRez made by @joevt which I think can show the negotiated modes - this info might help you figure out what's causing the issue. A possible way to fix the problem is to use EDID override to remove color modes or connection options from the mix that might require higher bandwidth to produce or create custom timings that help you better max out the available bandwidth (60Hz might not work, but 50Hz might or 60Hz with even more reduced blanking etc).