The news follows AMD's confirmation that it will keep the AM4 socket for its upcoming Zen 3 CPU to support older processor models. AMD explained that it will support X570 and B550 chipsets out of the box, but that the X470 and B450 will require a selective BIOS update. Support will not extend to X370, B350, and A320 chipsets.
To allow this to work, AMD has confirmed that in the case of motherboards requiring a BIOS update, these will no longer function with older CPU models despite having the same AM4 socket. Flashing the BIOS will effectively remove support for older AMD CPUs.
For the sake of example, anyone with a 300-series motherboard will need a new board if they want compatibility with the current 3rd-gen Ryzen CPUs as well as the upcoming Zen 3 chips. Conversely, anyone with a 500-series motherboard won't be able to use any chips older than the 3rd-gen Ryzen CPUs in the case of the B550, and anything older than the 2nd-gen Ryzen processors in the case of the X570 chipset.
Although there are caveats, the news is undoubtedly welcome among owners and confirms that the 400-series motherboards will be compatible with CPUs as far back as AMD Athlon all the way through to the next-gen Zen 3 architecture. The 400-series motherboards seem the best bet to bridge as many CPU generations as possible.
MSI confirmed as much, explaining that its 400-series motherboards will be compatible while the 300-series will lose out of support for the Zen 3 architecture.
While the situation certainly threw up several questions in recent weeks, the picture is a lot clearer now, allowing AMD motherboard owners to plan ahead.