We have almost 10 of ASOS ROG STRIX B350-F cards and Ryzen3 1200. We had some initial issues, but after flashing the latest BIOS we could just use default settings and 6 GPUs would work every time, no hassles.
Thanks. I can confirm I also had great results with this motherboard paired with a Ryzen 1300X. 6 RX Vega 56 GPUs up and running with no problems at all. Started with the latest BIOS. Easiest build yet.