Question HDMI - single 4K 60Hz to dual 1080P 120Hz & 75Hz

[harleychen]

I have 2 1080p monitors, one with a 144hz and the other with a 75hz refresh rate. Given that 4K 30Hz uses the same bandwidth as 1080p 120Hz, I bought a USB Hub which is adviersed as capable of doing single 4K 60Hz or dual 4K 30Hz HDMI outputs.

However, when I connect them up, I am no longer seeing the 120Hz option, the highest it will go is 60/75Hz... If I disconnect the 75Hz one (physically or in the display setting), I will be able to toggle back to 120Hz/144Hz on the other monitor.

Why is this and is there a solution for this?

 

[hang-the-9]

When you say "USB hub" do you mean a USB docking station with video out? If that's the case check with support for the maker of the dock if it can do what you think it should be able to do. They are the only ones that would know that.

 

[harleychen]

When you say "USB hub" do you mean a USB docking station with video out? If that's the case check with support for the maker of the dock if it can do what you think it should be able to do. They are the only ones that would know that.

It's a USB hub. https://www.vopmart.com/baseus-17-in-1-working-station-multifunctional-type-c-hub-adapter.html

I assumed that if it works for dual 4K 30Hz it will work for dual 1080p at the desired refresh rate. I thought it's a simple math equation that as long as there is enough bandwidth, it will be able to support it.