(Image credit: AMD)

AMD's Socket AM4 compatibility matrix just got very confusing. During the launch of the first-gen Ryzen processors, AMD delighted enthusiasts with its promise to support all of its Ryzen processors on AM4 Socket motherboards until 2020, but the company is encountering some difficulties delivering on that goal: The new X570 chipset doesn't support the first-gen Ryzen models, and motherboard vendors are steadily dropping support for older processors on existing Socket AM4 motherboards, too. We spoke with AMD and learned that the supported processor list could even vary depending on your motherboard or vendor.

(Image credit: AMD)

First and foremost, X570 motherboards will not support any of the first-gen Summit Ridge or Raven Ridge processors, so enthusiasts with first-gen Ryzen chips won't be able to step up to the latest and greatest motherboards. Meanwhile, X470 and B450 chipsets will support all generations of Ryzen processors.

But you won't be able to drop a new Third-gen Ryzen chip into all X370 and B350 motherboards, and A320's upgrade path is blocked entirely.

We had the opportunity to sit down with AMD CEO Lisa Su and her team after her Computex 2019 keynote and ask why the new Ryzen processors aren't supported on some of the older motherboards. AMD's Senior Technical Marketing Manager Robert Hallock fielded our question, explaining, "If we look across the ecosystem of motherboards that exist today, we certainly make BIOS updates available to our ecosystem partners to include that on different levels of motherboards in their portfolio, but I don't expect that every motherboard will be updated for 3000 Series processors from our partners. That really will be a portfolio decision from their standpoint as well, as to where they apply those updates, and where they choose not to apply those updates."

Due to the uneven application of BIOS updates across the various vendors, and even among different motherboards in the respective product stacks, you'll have to check the CPU support list for your X370 or B350 motherboard to ensure it supports Third-gen Ryzen.

The problem with backward compatibility boils down to BIOS chip capacity limitations, with AMD's portfolio of Ryzen processors swelling to the point that most BIOS chips do not have enough capacity to store all the microcode and memory training tables for all of the processors.

AMD's goal to support all Ryzen processors on Socket AM4 motherboards until 2020 was audacious, but one the company is proud of, "No one in the history of x86 has created an upgradeable socket quite like AM4. In a time where our competitor is breaking socket compatibility yearly, basically, we have three consecutive generations that all drop into the same socket, and that socket started with four cores years ago, and is now twelve cores, twenty-four threads and PCIe 4.0," said Hallock.

(Image credit: AMD)

Finally, there are plenty of X470 and B450 motherboards still on the market, but some of the boards that have been in the supply chain for a while will need a BIOS update before you install a Third-gen Ryzen processor. As we've seen in the past, that isn't always possible if you don't already have a Ryzen processor or if the motherboard doesn't have an out-of-band BIOS update feature, like BIOS Flashback. AMD also announced that all motherboards that support Ryzen 3000 processors out of the box will come with a new badge to help simplify things.