It seems that a few PC enthusiasts have successfully managed to get the new Ryzen 5000 series processors, to run on AMD’s 1st generation 300 series AM4 motherboards. Specifically, they managed to get it running on an entry-level A320 and high-end X370 motherboard.
In the case of the X370, the individual – he made a post on overclock.net about it – managed to pull off the feat by flashing his Gigabyte X370 motherboard with what we can only assume is a custom “beta BIOS” with AGESA code that supports the Zen 3 architecture. The only shortfall to the BIOS is that PCIe Gen4 is disabled because…well, AMD’s 300 series motherboards just don’t support the interface. Another forum user from the China-based forum, Chiphell, proved it was possible by posting a picture of his A320 motherboard running with a Ryzen 9 5900X CPU, after he had flashed the motherboard’s chipset with an unofficial BIOS too. Proving that AMD’s statement about its Zen 3 processor not being backwards compatible with older motherboard doesn’t quite hold water.
Again, the method in which these enthusiasts managed to get the new Ryzen 5000 series working on 300 series motherboards seems to require some technical know-how to customise the BIOS. Further, it is still very unlikely that AMD will officially provide enthusiasts with the means and support for backwards compatibility with previous generation motherboards. Especially ones that are two generations behind. (Source: Overclock via Hot Hardware, Chiphell)
