AMD won't support PCIe 4 on pre-X570 motherboards after all

Gigabyte AORUS motherboard
Gigabyte AORUS motherboard (Image credit: Windows Central)

What you need to know

  • AMD has decided not to allow PCIe 4.0 support on older socket AM4 motherboards.
  • The company says it made the decision because a lack of clarity on which motherboards could reliably run PCIe 4.0 would cause confusion in the market.
  • To get PCIe 4.0, you'll have to use one of AMD's new Ryzen 3000 series processors with an X570 motherboard.

AMD this week revealed that it won't support PCIe 4.0 on older motherboards with its Ryzen 3000 series processors. Though the new processors support the feature and are compatible with the same AM4 socket present on older motherboards, AMD says that it can't guarantee a reliable experience on motherboards that weren't designed with PCIe Gen 4 in mind.

In a Reddit post (via PC Gamer), AMD senior technical marketing manager Robert Hallock explained the move:

This is an error we are correcting. Pre-X570 boards will not support PCIe Gen 4. There's no guarantee that older motherboards can reliably run the more stringent signaling requirements of Gen4, and we simply cannot have a mix of "yes, no, maybe" in the market for all the older motherboards. The potential for confusion is too high.When final BIOSes are released for 3rd Gen Ryzen (AGESA 1000+), Gen4 will not be an option anymore. We wish we could've enabled this backwards, but the risk is too great.

In a statement to TomsHardware, AMD elaborated further, stating:

As pre-X570 motherboards were not designed with PCIe 4.0 in mind, their designs may be incapable of running PCIe 4.0 signaling with the requisite stability and performance. To ensure a reliable and consistent experience in the field, PCIe 4.0 will not be an option ultimately available to pre-X570 motherboards. Users may continue with a beta BIOS if they desire, but performance and stability cannot be guaranteed.

If your motherboard has already received an update that added PCIe 4.0 support, AMD says that it will be pulled when the final BIOS updates are released to support the 3rd Gen Ryzen processors.

So, in order to take full advantage of the PCIe 4.0 support arriving with the Ryzen 3000 series, you'll need to have one of the new processors running on a motherboard with AMD's new X570 chipset. We've seen several X570 motherboards shown off ahead of AMD's 3rd Gen Ryzen launch, including a new collection from MSI.

PCIe 4.0 greatly increases the speed with which storage drives and graphics cards can send data on your PC. Some early PCIe 4.0 SSDs from Corsair and AORUS have teased read speeds upwards of 5,000 MB/s, which is incredibly fast.

The new Ryzen 3000 series is expected to go on sale in July with prices starting at $199.

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Dan Thorp-Lancaster is the former Editor-in-Chief of Windows Central. He began working with Windows Central, Android Central, and iMore as a news writer in 2014 and is obsessed with tech of all sorts. You can follow Dan on Twitter @DthorpL and Instagram @heyitsdtl

  • Question: is PCIe 4.0 not a hardware change? I was under the impression that PCIe 4.0 slots were necessary to use it (obviously PCIe 4.0 devices as well), not that it was purely controlled by the CPU/Motherboard chip firmware (ie. Just upping the clock speed). Or is it strictly a software change on the motherboard/CPU side? To my limited knowledge PCIe 4.0 motherboards hadn't gone up for sale previously anyway, so are there any other BIOS chips that support it?
  • Consider this train of thought:
    We now have CPUs whose internal connections are now about 4x the thickness of an atom or smaller than the wavelength of light required to make them with problems from the quantum realm now being a thing of consideration ( or so I read ) and here they say that the previous' generation Motherboard PCIe traces, large enough to be hand drawn by a human, cannot handle signal integrity to support what appears to be a software-only achieved bump in performance ( otherwise they wouldn't say it might be possible on a case-by-case situation ). *raises an eyebrow*
  • I think your concept of 'software-only' is causing the confusion. If PCIe 4.0 was 'software-only' - it could be turned on for any older CPU on any hardware with the PCIe 3.0 wiring. (See how this breaks down the idea, and is not 'software-only'?) Mainboards are complex, and even a tiny change in something that would seem insignificant, like spacing as one tiny example, being the difference between working or not.
  • I'm actually surprised AMD even considered it would be feasible, although *technically* the wiring of PCIe 4 is the same as PCIe 3 (and 4 is backwards-compatible to all previous gens).
  • The very idea of getting a performance improvement, for free, is absurd. These companies are out to make cash. If it were not for that fact PC development, as well as most things in life, would be far, far more advanced than they are now. Sell the people the same stuff, that they already have, with the minimum amount of performance increase possible. $$$$/££££.