I'm using Arch with i3 and I'm trying out the new 3D viewer. It's horribly slow. Rotating the board by more than a couple 10's of degrees causes the application to hang for about 6 seconds and then it begins to respond again. Turning off more and more layers, like soldermask, for instance, helps, but doesn't cure the issue.
I'm running an Intel graphics card on a Dell Latitude E6420 and I've got the xf86-video-intel and the mesa-libgl packages installed.
It appears (although this is pure speculation because I'm not sure where to look) that there is simply no hardware acceleration for 3D rendering enabled whatsoever. The slightest update in the scene causes KiCad to choke, big time.