Stefan Mileschin

Following this week’s launch of AMD’s new Ryzen 3000 series of processors, reports have once again begun circulating that PCIe 4 will be available on some existing 300 & 400 series boards. This comes despite AMD’s official statement last month that they would not be allowing the feature on older boards, as PCIe 4’s tighter signal integrity standards would have led to, at best, a highly fragmented market where some boards work, some boards don’t, and some boards may be outright marginal. At the time the company stated that the feature would be stripped from the AGESA that goes into the final Ryzen 3000 launch BIOSes for older boards.

So, to get right to the heart of matters, I reached out to AMD PR this evening to find out what’s going on with PCIe 4 support. The short version then is that no, AMD’s plans have not changed: PCIe 4 support will be disabled in the shipping AGESA for these boards.

Our plan is unchanged. For the reliability and consistency reasons cited at Computex, we still intend to disable PCIe Gen 4 for pre-X570 motherboards. That AGESA is being released to motherboard manufacturers soon.

As things stand, any boards that currently support the feature would be using pre-release AGESAs, and as we’ve seen with our own BIOS issues, the Ryzen 3000 BIOS situation is still evolving fast. So with AMD intending to permanently disable the feature – and prevent any workarounds – AMD’s goals haven’t wavered. At best, the few boards that have beta BIOSes with the feature will lose them in the future, unless users opted to stick with an unsupported (and almost certainly buggy) BIOS.

Going forward, proper PCIe 4 support will continue to require an AMD 500-series board specifically designed to meet the signal integrity requirements for the higher speed standard. Right now, this includes boards based on AMD’s X570 chipset; and while the company hasn’t announced other 500-series chipsets, we’re expecting to see more in due time.

https://www.anandtech.com/show/14639...-series-boards