Sources have told Moore's Law is Dead that the flagship models of the upcoming Intel Z790 motherboards will feature PCIe Gen 5 M.2 SSD compatibility, but not the mainstream variants. Among AMD's approaching AM5 boards, the M.2 slots for the X670 Extreme, X670, and B650 will be PCIe 5.0.
https://www.techspot.com/news/95181-flagship-intel-z790-motherboards-expected-support-pcie-50.html?utm_source=dlvr.it&utm_medium=blogger
https://www.techspot.com/news/95181-flagship-intel-z790-motherboards-expected-support-pcie-50.html?utm_source=dlvr.it&utm_medium=blogger