any Idea what might cause this?
it happens but only occasionally when I try to run World of Warcraft through Wine.
It seems to be very much video-card related, but I can’t seem to pin it down.
The screen will turn black, then display the above, then crash completely and reboot.
Which DE are you using, plasma?
Difficult to say, you need to give more information so the forum can help you.
For example what graphic card are you using and what driver?
Check also the Arch wiki, there is must be a terminal command that logs crashes and you could post it here.
From my previous experience with Plasma, the compositor for OpenGl can be inspected and some settings changed. Obviously I do not know much about it, but its under
System configuration > Desktop effects > Advanced > Compositing type, for example you can try to select “XRender” instead of the default OpenGL, or there may be other options. You need to do some research.