Hi friend,i have seen your post on Facebook group.And i have the similar rig system with you. Currently I don‘t know it is the problem of the AMD platform+20 series card hardware rig. Or it is the driver and software issue.

Having seen many posts have issue with x399 motherboard with 128GB RAM and ...

This is most likely not a bug for us. More likely a hardware problem.
Could you please update your driver? Also try to disable some gpus for testing?

I have tried the lastest Gameready and Creatorready drivers but didn't help.
I can use all GPUs with redshift and Octane benchmark is fine.So it ...

A. win10 pro
B. 4xAsus turbo 2080ti
C. 128GB
D. Nvidia Creator Ready Driver 419.67
E. OctaneRender Standalone version 4.02.1
F. OctaneRender plugin version 4.02.1-R3
G. Cinema 4d R19

I got my new machine month ago.When I click render button the system frozen and crashed.Most time I can't even move ...

when i turn off the camera visibility ，shadow pass seems not the right result.