FYI: this on OS X El Capitan with Blender 2.81a.
I copied the attached material from a youtube tutorial for Blender 2.80. I made some modifications to the original, but the only stickler seems to be the Bump map. Every time I connect the Bump map normal output to to the shader's normal input, Blender goes off to beachball land. Seems to work fine in 2.81a Cycles.
Is there something I'm missing or a bug I don't know about?