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PCIe 4.0 “will not be an option ultimately available” to non-X570 AMD Ryzen chipsets

PCIe 4.0 is to be disabled on pre-X570 boards when final retail BIOSes are released to "implement full performance and stability."

AMD Ryzen 3000

AMD’s Ryzen 3000 processors are nearly upon us. These will arrive July 7 alongside X570 motherboards and RX 5700-series GPUs – all fitted with PCIe 4.0 capability to supercharge your rigs bandwidth. Older motherboards are also welcome due to AM4’s backwards compatibility, some even capable of limited PCIe 4.0 capability with the right BIOS config. However, according to AMD, this germinal functionality may be nerfed in final retail code.

As it stands today, most X470 and B450 motherboards have a BIOS available that ‘unlocks’ PCIe 4.0 speeds on a limited number of PCIe 4.0 slots. You may have noticed the option for PCIe 4.0 appear in your BIOS settings following a recent update. However, while that looks to still be the case, AMD is touting this as “beta” functionality (via Vortez), and, while it may work in some cases, the red team doesn’t want to be the one responsible for any uncertain stability post-launch.

“Users today may find a PCIe 4.0 option available in their pre-X570 motherboards,” AMD says to Vortez. “However, users should expect this option to be disabled when final retail BIOSes are released to implement full performance and stability for new 3rd Gen Ryzen processors.

“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.”

Read more: These are the best AMD gaming motherboards pre-X570

You may still opt to stick with a beta BIOS and ensure some PCIe 4.0 capability. However, in doing so you may be choosing to nerf your ability to update later down the line.

AMD has previously said that PCIe 4.0 is a “more demanding PHY”, that requires stringent signalling requirements and material requirements in order to operate correctly.

Compatible with Compatible with Compatible with Compatible with Compatible with
X370 Selective Beta BIOS update needed.
B350 Selective Beta BIOS update needed.

To ensure the smoothest transition, you’ll want to follow the above table closely. AM4 is still the socket of choice for AMD’s mainstream processors making for an easy upgrade for some, but you’ll still need to read up on the ins and outs of the process to avoid any potholes along the way.

If in doubt, look for the “AMD Ryzen Desktop 3000 Ready” badge at retail. This will be attached to all new motherboards fitted with the correct BIOS for AMD’s Zen 2 desktop processors.

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