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.

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  • TheUnhandledException - Friday, July 12, 2019 - link

    AMD might not officially support it but there is little they can do to stop OEMs. Since OEMs intend to keep selling X470 boards support for PCIe "official" or not will become a selling feature. Brands that enable it will sell better than those that don't.
  • nevcairiel - Saturday, July 13, 2019 - link

    Actually there is little OEMs can do if AGESA flat out blocks it. On AMD platforms the OEMs really don't have that much influence on the core workings of the BIOS, unlike on Intel where they have all the control.

    Also, I'm sure AMD has contracts with these companies and can dictate a lot of things.
  • jharrison1185 - Saturday, July 13, 2019 - link

    They can always withhold shipments of X570 chipsets and Navi GPU,s to board vendors that would choose to circumvent their policy. And frankly I would be shocked if any board MFR offered it anyway as they would want to sell new motherboards anyway. That doesn't however mean that some very tech savvy people couldn't do it themselves, but I would not risk bricking my MB with a nodes bios.
  • FreckledTrout - Sunday, July 14, 2019 - link

    Really there will be no pissing contest. The motherboard vendors aren't exactly quaking in their boots to back port PCIE 4.0 to older boards especially since the new boards cost more.
  • evernessince - Sunday, July 14, 2019 - link

    It's a good think AMD has a lot of control over the basic workings of the CPU and chipset. It means more consistency across the platform.
  • InvidiousIgnoramus - Saturday, July 13, 2019 - link

    That's quite literally what they're doing by stripping it from AGESA, lmao.
  • Jansen - Saturday, July 13, 2019 - link

    The old school perception that AMD has been fighting for 30 years is that AMD has inferior products and that it's not as reliable as Intel.

    In order to fight that perception, they need to have products that are consistently faster, cheaper, and more reliable right out of the box. Having even a few models of older motherboards not work with PCIe 4.0 would muddy the waters and cast doubt once again. It would cause confusion in the marketplace and play right into Intel's hands.

    Really, AMD is trying to support its customer base by keeping the socket the same. Sure, it would be nice to have PCIe 4, but the new Radeon RX 5700 will still work fine on PCIe 3. If you really want PCIe 4 you can always sell your old board and buy a new one, but I suspect most people will be ok just keeping their old one.
  • Jansen - Saturday, July 13, 2019 - link

    There is a strong possibility that in 12-15 months you will see the X670 chipset with PCIe 5.0 and Zen 4.
  • bananaforscale - Saturday, July 13, 2019 - link

    Unbloodylikely given that Zen 4 would be two generations and you don't really need PCIe 4, let alone 5. The use cases are so rare there's basically no reason to implement it.

    Sure, those things will happen, but not in that timeframe.
  • ajp_anton - Monday, July 15, 2019 - link

    Well, one use case is, you know, the chipset. It's limited to 4 lanes, so in order to reduce this bottleneck, more speed per lane is needed.

    Now, with PCIe4, that bottleneck has widened compared to old chipsets and Intel, but you can still choke it by connecting lots of things to the chipset.

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