I just upgraded my X370 board from a Ryzen 1600X to a 3700X. But when i boot with the new CPU, everything turns on (even mouse and keyboard has lights as normal), but my monitor gets no connection - the monitor doesn't start.
I have updated to the latest BIOS of course. And i can boot normally if i put back in the old 1600X CPU again.
According to the manufacturer, the motherboard does indeed support the new CPU as long as you run a newer version of their BIOS. The board is an ASUS X370-F.