With Viz 2020 SP1, I had issues with it switching to the CPU during GPU renders within the first 200 passes. Did a little research, turns out that SP2 is current. So, upgraded to that. Now, instead of switching to the CPU within the first 200 passes, Visualize just tells me that the background render failed.

I can do a seemingly unlimited number of passes in the viewport without this happening.

Where do I start with troubleshooting?

Machine has a 9980xe with some Titan RTXes in it. I have Viz set to use only two of the GPUs for rendering.

I do not run into this issue with 2018.