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
Do B450 Motherboards Support Ryzen 5000? (BIOS FAQ)
AMD Chipset Comparison: B550 Specs vs. X570, B450, X370, & Zen 3 Support (2020) | GamersNexus - Gaming PC Builds & Hardware Benchmarks
MSI confirms AMD Zen 3 support for its B450 and X470 motherboards - NotebookCheck.net News
AMD Ryzen 4000 Zen 3 will be compatible with Socket AM4, but it is end of the road for X470, B450, and below motherboard owners - NotebookCheck.net News
AMD Backtracks: B450, X470 Motherboards WILL Now Support Zen 3! - YouTube