Operating system: Catalina 10.15.2
Graphics card: RX 5700 XT
Broken: 2.81.16 , 2.82 Alpha (from November 29/ buildbot)
Broken: 2.82 Dec 11 2019
Worked: (optional) 2.81 on windows 10
Worked: 2.80.75 on Catalina 10.15.1
Worked: 2.80.75 on Catalina 10.15.2
Short description of error
Despite the solved error in T71147 the EEVEE viewport performance (Material Preview, Render) are very slow.
Test scene: https://download.blender.org/demo/eevee/archiviz/archiviz.blend
You can't manipulate by mouse (pan, zoom... very-very slow).
On the same Mac under Windows 10 partition everything works good without performance degradation.
Exact steps for others to reproduce the error
Based on the default startup or an attached .blend file (as simple as possible).
Try with this demo-file: