uga-4khdmi so sluggish in 4k mode that it's unusable for anything other than as a static display


#1

I have Windows 10, 32gb memory, 1tb ssd, i7-6950X CPU (Passmark ~20k). I’m using a Samsung 49" curved screen.

I am connecting a pluggable uga-4khdmi over USB 3.0. Display is incredibly laggy, it’s almost unusable. I have to wait a second or two just to be able to correctly position the mouse over a UI button. It takes about .05 to 1 second for my action to reflect in the UI, i.e. if I clone my native screen, in a movie, there is a very noticeable delay in what the cloned pluggable 4k USB screen shows compared to real-time.

I noticed WUDFHost.exe (USB driver interface that plugable 4k driver apparently uses) takes up < 0.01% cpu usage, unless I have the mouse in the 4k screen or the 4k screen is being updated with a pixel change.

It takes up > 20% CPU when just moving the mouse on the 4k screen.

This is more processing power than it takes to render 4k video in software on my natively connected screen, or, more CPU power than it takes to decode 22 MB/s of LZW compressed data… More CPU power than it takes to play most games in fact…

…just to move the 24 pixel mouse cursor? What is going on?


#2

Hi Nicholas,

Thanks for posting! A few quick points, our UGA-4KHDMI adapter when running at 3840x2160 is limited to a 30Hz refresh rate so that may account for some of the lag you are seeing. Our adapter also depends on your CPU (via the DisplayLink driver) to drive the connected display, so the CPU usage in its associated process can vary.

Moving forward, you mention you are cloning your internal display to the monitor connected to the adapter. As a first step, if you switch to ‘Extend’ mode as opposed to ‘Duplicate’ mode as you are now, does that help with the performance?

Thank you,

Bob
Plugable Technologies
www.plugable.com/support


#3