AMD occasionally touts the longevity of the AM4 socket, but this comes with a caveat: AMD confirmed less than two weeks ago that its next-generation Zen 3 CPUs will be compatible with socket AM4 motherboards, but only the 500 Series Mobo (X570 and B550) The only compatible boards are the 500 series Mobo (X570 and B550). That means your snazzy X470 motherboard won't support the next AMD processor. Or at least it did. Now AMD has stated that it has "decided to change its policy" regarding Zen 3 support on X470 and B450 motherboards.

"While it would be nice if all chipsets could fully support all processors, the flash memory chips that store BIOS settings and support have capacity limitations. Given these limitations and the unprecedented longevity of AM4 sockets, there will inevitably come a time and place where a space-saving transition is necessary.

AMD seemed to be trying to avoid a repeat of previous situations where they had to loan out chips to DIY builders who wanted to combine next-generation CPUs with older-generation motherboards. [But in any case, AMD has now announced that its X470 and B450 motherboards will indeed support Zen 3

. As a result, we will be offering an upgrade path for B450 and X470 customers to add support for the next generation of AMD Ryzen processors in the 'Zen 3' architecture," AMD announced today on Reddit.

AMD said that this decision is "very new" and that "many details still need to be worked out," and that it will provide more details in a blog post closer to the Zen 3 launch. Meanwhile, AMD provided a bit of preliminary information on how this will work.

Apparently to make room in the cramped BIOS, AMD said that an optional firmware update adding support for Zen 3 would disable support for "many existing" Ryzen processors. AMD did not say which ones, but it did say that the first generation Zen CPUs (Ryzen 1000 series CPUs and Ryzen 2000 series APUs) would be truncated.

Another interesting tidbit is that anyone who decides to flash a beta BIOS to add support for Zen 3 must have supreme confidence in their decision. In the unlikely event that they change their minds and want to revert to the previous BIOS, they are out of luck.

"Some beta BIOSes will allow a one-way upgrade path for AMD Ryzen processors with 'Zen 3' coming later this year. Flashbacks to older BIOS versions will not be supported," AMD stated.

In any case, while we can't imagine many people wanting to downgrade from a Zen 3 to a Zen 2 CPU, the risks of a one-way upgrade extend beyond the CPU: if the BIOS update somehow breaks functionality or causes other issues ( onboard Wi-Fi becomes unstable or everything stops working), it would be unfortunate.

Risks aside, this is a good move by AMD. This is also the demise of the X470 and B450.

"This is the last path for AMD to add new CPU support to 400 series motherboards; CPU releases after 'Zen 3' will require newer motherboards," AMD added.

Of course, assuming AMD eventually adopts a new socket for Zen 4,