As stated in this thread, Ubuntu 18.04 looks like it has some trouble with AMD Ryzen 5 integrated graphics controllers, where Ubuntu freezes occasionally, including the mouse. I can prove this issue for also dedicated graphics controllers (RX570).

There must be an probably undocumented issue with the new Wayland or what so ever. The result of this question should be to collect enough information or a solution to file a bug report against the community.

The user @SD has solved the problem in switching the environment to metacity (sudo apt install gnome-session-flashback). He says that this issue could not only be related to just internal GPU's.

Also, which environments might work besides the mentioned ones?

  • What if you would exterminate that wayland thing and you would use pure X11? – peterh - Reinstate Monica May 13 '19 at 15:56
  • as a follow up. The mesa-driver version of 18.04 is pretty old. my assumtion are that the problem is fixed in newer versions. I took adventage of the newest ubuntu. an other opportunety would have been to install the newest drivers by hand. – Cutton Eye Jun 11 '19 at 12:31
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    The cause of that X is so slow, is not the X11 protocol. The cause is that there is not enough human resource to write the X11 apps correctly. X should be multi-threaded and event-oriented, it is only event-oriented. The X11 apps should be multi-threaded and event oriented, most of them are not. Wayland does not solve these problems. A "wonderful" new idea to "replace X" happens in every five years, wayland is only the next step of the failed experiments like svgalib, fbcon and ggi. – peterh - Reinstate Monica Jun 11 '19 at 13:00
  • started a new thread here: askubuntu.com/questions/1155200/… – Cutton Eye Jul 1 '19 at 10:52
  • This is exactly the question type what we so hate here. You say a mysterious bug, but your question is more mysterious than your bug. – peterh - Reinstate Monica Jul 1 '19 at 11:19