If PCIe 4.0 is generalized thanks to AMD and its latest Ryzen 3000 platform but it is only a step. The PCI-SIG is already working on the next generation. It will go through PCIe 5.0 then PCIe 6.0.
Announced in June 2019, PCIe 6.0 should be finalized in 2021. Work on its specifications is in progress. Version 0.5 was even released by PCI-SIG last week. This is an important step towards the final version. In this regard, two intermediate developments are planned with the publication of versions 0.7 and 0.9.
On the occasion of this announcement, the press release specifies.
PCIe 6.0, see you in 2021
We now have important hints about features and planned design changes. For example, the bandwidth will quadruple compared to the current PCIe 4.0 and doubled compared to the PCIe 5.0. Backward compatibility with older standards is expected. Suddenly it is possible that the format remains identical.
PCIe 6.0 will also offer FEC (Forward Error Correction) and will implement PAM4 on the power supply instead of the NRZ present in PCIe 5.0. If the goal of completing this standard is set to 2021, it will take a little longer for its democratization.