Created attachment 727864 [details]
hwinfo output

this is actually a Leap 42.2 system with a Tumbleweed kernel and Xorg from
X11:Xorg repository
(because otherwise on 42.2 the RX480 doesn't work at all?)

in Xwindows, the desktop randomly flickers. The whole screen blinks for a frame
or two, or maybe some artifacts are shown that disappear immediately. This
happens intermittently, intervals ranging from a couple minutes to a couple
seconds.
I couldn't tie this to a particular action, the screen even flickers when left
completely alone and nothing is visibly changing.

This doesn't depend on whether a compositor is turned on or off, nor on the
rendering API the compositor is using. I have tested KDE Plasma (my primary
desktop), MATE and IceWM, and the flickering is present in all of them (and in
the KDM login screen as well), although it seems to happen less frequently
without compositor in KDE and even less frequently in IceWM.
So, somehow tied to "graphical intensity" of what is going on?