Will Ryzen 5000 be compatible with B450 motherboards? - Quora
AMD Ryzen 5000は300シリーズマザボでも動作。B450向けBIOSも登場
AMD Ryzen 5000 Zen 3 support is rolling out for ASUS, ASRock, Biostar, Gigabyte and MSI 500 series motherboards; no B450 or X470 support until January 2021 at the earliest - NotebookCheck.net News