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
Socket AM4 has proved to be a very good investment for AMD. It has seen quadrupling of cores from the 4C/4T Ryzen 3 1200 to the 16C/32T Ryzen 9 3950X, four architectures and process improvements, PCIe Gen4 support, and more. AMD's Socket AM4 came as a relief at a time when Intel required (and still does) a complete motherboard upgrade with each new generation.
With Zen 3 set to launch in the coming months, AMD's consumer Technical Marketing Lead Robert Hallock clarified a few aspects about compatibility of Zen 3 with Socket AM4.
In a blog post, Hallock confirmed that current AMD X570 and B550 chipset motherboards will support Zen 3 processors after a BIOS update. However, Zen 3 processors will not be compatible with any chipset prior to X570 or B550. This means end of the road for all those who have X470, B450 and below chipset boards. Hallock says that this decision had to be taken as due to BIOS capacity limitations on older platforms.
We've seen AMD taking a similar stance with Zen 2 as well by removing drop-in support for motherboards that have just a 16 MB EEPROM. X570 motherboards have a 32 MB EEPROM thereby enabling larger a AGESA codebase to be comfortably accommodated.
Hallock did not offer a specific timeframe for transition to a newer socket and said that it depends on the timeline of industry I/O technologies. He said,
Such technology changes typically require adjustments to the pin count or layout of a processor package, which would necessitate a new socket. We have no specific details to share concerning this roadmap or timing right now, but we know it’s important to keep you updated—and we will."
This sentiment was also echoed by AMD Senior Director of Product Management David McAfee back during E3 2019, who said, "It will really take a major inflection point in the platform technology for us to move off of socket AM4". We can expect PCIe Gen5 and DDR5 to debut in 2021, which would probably necessitate a new socket (AM5?) for Ryzen 5000.
While Zen 3 will be fully compatible with current X570 and B550 motherboards, AMD is also expected to introduce the X670 chipset this year, which will be made by partners such as ASMedia and Via. The exact features of the X670 chipset are still not clear, but we expect better PCIe Gen4 implementation and more connectivity for NVMe, SATA, and USB 3.2.