Gigabyte has released PCIe 4.0 with the F40-UEFI on some AM4 motherboards. The update is available for all motherboards of the manufacturer with AM4 slot and B450 and X470 chipset.
Until now, users of these motherboards in UEFI could select the PCIe standards “Gen1”, “Gen2” and “Gen3” in addition to “Auto”. The UEFI update makes “Gen4” available as a new option. Current Ryzen 200 processors do not yet support PCIe 4.0.
So the UEFI update seems to be an update for the upcoming Ryzen 3000 processors, which are also supported by the updated motherboards. PCIe 4.0 requires a better signal quality due to the higher transfer rates. The length and spacing of the traces are the most important factors here. Whether the old motherboards will really be certified for PCIe 4.0 by the now distributed UEFI update is questionable. Gigabyte has not yet issued a statement on this issue.
Further information will probably be revealed at the Computex soon to be held.