Many of us noticed this in the most recent blender version, it´s unstable and developers says that it might be a driver problem here: T77095 Artefacts when rendering with the GPU in Blender 2.90.2 and 2.83 release
How to reproduce:
1.- Having any polaris graphics card.
2.- On blender 2.83 enable opencl on edit>preferences>devices>Opencl and enable gpu.
3.- Just enter render view and it will show the artifacts.
I´m using the driver 20.50.1 and it´s present in 20.4., any ideas of how to fix it? or can it be fixed on a driver update?.
Definitely a driver problem, this bug isn´t present on drivers version 20.2.2 and older, only affects newer versions
Can confirm on my end, rx570 4gb
Driver 20.2.2 and earlier works fine, anything later and the artifacts and crashing occur
Worked fine in Blender 2.82, but only because it didn't utilise OpenCL 2.0
Also i confirm having issues with cycles on a rx580 8gb, the people at Blender gave us an Alpha that worked ok. Downgrading cause some UI glitches so we need a workaround for the next update!