Hello, I brought a new RX 5700 XT gpu last week (Sapphire Nitro+ RX 5700 XT SE) and it seems like the opencl is broken.
It started with persistent crashes when using blender, and then I discovered that there is some persistent computation error when using the plaidml benchmark tool (for example the mobilenet benchmark).
I am using Linux, but there's a few others that using Windows that has similar issues.
I am using the latest AMDGPU-PRO version (20.40).
You can see the discussion on the blender developers forum that's going on for months:
T78027 Render crashes Blender when used with Volume Absorption