Operating system: Darwin-19.3.0-x86_64-i386-64bit 64 Bits
Graphics card: AMD Radeon Pro 560X OpenGL Engine ATI Technologies Inc. 4.1 ATI-3.5.5
Broken: version: 2.83 (sub 15), branch: master, commit date: 2020-04-29 19:35, hash: rBcd833d887995
Worked: 2.83 (sub 13), branch: master, commit date: 2020-04-13 08:07, hash: rB2ec6eca518ef
Short description of error
When playback is on the FPS goes down to 5 when the armature is visible. The same file works fine on a branch from a few days ago.
Exact steps for others to reproduce the error
Add a Monkey, subdivide by 3, apply.
Add a human meta rib, Generate Rigify Rig.
Select Monkey, the rig and Set Parent With Automatic Weights.
Enter Pose Mode, add keyframes for a short animation moving and rotating random bones.
Playback with the Armature visible then hide it and see the difference.
It works fine on the human rig without the Rigify "Generated Rig", so it might be related.