It’s good to know that even the B350 chipset supports the new 3000 series RyZen CPU’s.
Not long after I made my last post, I found a video on YouTube of an 3900X running on an B350 chipset board. I can’t find the video at the moment.
The only comment the person made was, the VRM’s were getting a bit hot. But that’s to be expected when such a CPU is running on board that it wasn’t designed to run on.
Regarding PCIe4. Since NVMe is run directly from the CPU on RyZen. You will get PCIe4 speeds from an PCIe4 NVMe SSD, even on an X470 or X370 motherboard.