Given recent information, AMD reiterates that ONLY X570 motherboards will support PCIe 4.0
To avoid confusion, AMD reaffirms that ONLY X570 chipset motherboards will have support for the PCIe 4.0 interface
During Computex 2019, AMD wanted to make it clear that only X570 motherboards would support PCIe 4.0. Just yesterday leaked from china that some ASUS motherboards would support PCIe 4.0. The leak was rare, because there was talk that many B450s would support this interface. These motherboards are usually very simple and hard to believe. To avoid problems and confusion, AMD wanted to reiterate that ONLY X570 chipset boards will support PCIe 4.0.
The company already said weeks ago that using the AGESA microcode it would eliminate compatibility. So there would be a BIOS lockout to prevent an X470 or B450 motherboard from supporting PCIe Gen4. Anandtech, after yesterday's information, contacted AMD, who has confirmed that this will not happen.
No motherboard with X470 or B450 chipset will support PCIe 4.0
AMD has wanted to be emphatic about it: “our plans have not changed. For the reliability and consistency reasons cited in Computex, we continue with our intention to disable the PCIe 4.0 interface prior to the X570. This version of AGESA will be distributed shortly to motherboard manufacturers "
This contradicts the latest information and at the moment, there is no one with a mobo with an X470 chipset that claims to have PCIe 4.0 support. Apparently the latest BIOS, at least ASUS, if they would support it. While AMD insists that no chipset, except the X570, will support PCIe 4.0.
It is unknown at this time if motherboard manufacturers will have the ability to bypass this restriction. Gigabyte or MSI announced PCIe 4.0 backward compatibility, but in the face of AMD's refusal, nothing else was known about it. If anyone skipped it, it would be in very premium models, capable of supporting it, it seems unlikely that a motherboard with a B450 chipset can support PCIe 4.0.
We must be attentive. If any update and within the BIOS find support for PCIe 4.0, let us know and we will let you know.
