Very low performance with AMD Ryzen Pro 4750U

[dominik.zogg]

I bought a Club Dual 4k Dock (Displaylink):

I got to notebooks, one for work, one for private, both running Ubuntu 20.10
The first got a Intel® Core™ i7-10710U Processor and the dock works well.
The second got a AMD Ryzen Pro 4750U and the performance of the external sceens is very low.

Moving windows redraw that slow that it looks like wobbling, parts of the window are moved others aren't. Mouse cursor feels a bit more fluid, but far from usable.

[Blafasel]

I got exactly the same issue. Processor is a AMD Ryzen 4800H with integrated graphics (no dedicated graphic card).

When I connect a monitor directly to my Laptops HDMI Output, everything is great.

Via the docking station its basically unusable, even Youtube Videos have a lot of fragmentation going on while playing. It seems like the signal is separated into several horizontal blocks and they get updated one after the other with a noticable delay between each block.

[ff801]

same here. performance is really bad. basically this stuff is unusable.

[irvis]

Hey,
Sorry to write it, but same here.
Tried on Ubuntu 20.04 and 20.10.
Drivers version tried 5.3.1.34 and 5.4.0-55.153.
Laptop:

• Processor: AMD® Ryzen 5 pro 4650u with radeon graphics × 12
• Graphics: AMD® Renoir

System:

• Gnome Version: 3.38.3
• Kernel: Linux 5.8.0-50-generic x86_64
• OS: Ubuntu 20.10

All works good, until I plug in docking station. Then system seems to behave like drunk old man. I get out of nowhere latency between click and run program, each window is fragmenting once moving, unusable, not able to work on that
as I recall on Ubuntu 18.04 and 18.10 it was ok. So I suspect drivers.

Do you think this can be connected with issue described here