Just tried software rendering for comparison. Using softpipe ETR runs like on
amd64 without any glitches. Albeith unuseable slow on a G5.

$ glxinfo | grep -i opengl
OpenGL vendor string: VMware, Inc.
OpenGL renderer string: softpipe
OpenGL core profile version string: 3.3 (Core Profile) Mesa 18.0.0-rc4
OpenGL core profile shading language version string: 3.30
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 3.0 Mesa 18.0.0-rc4
OpenGL shading language version string: 1.30
OpenGL context flags: (none)
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.0 Mesa 18.0.0-rc4
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.00
OpenGL ES profile extensions: