Speaking of PCI-e GEN version,
PCI-E 6.0 has already been announced and drafted by
PCI-SIG.
IMO, PCIe 6.0 is the new hotness, packing a 2x increase in transfer speeds over PCIe 5.0, a 4x boost in raw bit rate over PCIe 4.0 and a whopping 8x improvement over the 32GB/s of bandwidth that an x16 PCIe 3.0 configuration can offer.
PCIe 6.0 is a standard that's currently within its planning stages, with PCI-SIG planning to ratify and release their full standard in 2021, two years after the release of PCIe 5.0. In the PC space, it typically takes two years for PCIe standards to make it into the PC market, making it probable that we will start seeing PCIe 6.0 compliant PCs in 2023 or 2024.
To put the performance of PCIe 6.0 into context, it could enable M.2 devices to deliver speeds that are up to eight times faster than today's Samsung 970 Pro series SSD, which is widely regarded as one of the best performing M.2 SSDs on the market.
PCIe 6.0 should enable higher levels of
bandwidth for those who need it while granting PC users access to today's bandwidth levels over fewer PCIe lanes. The only problem with this rapid evolution is that new PCIe 4.0 devices will soon find themselves replaced with PCIe 5.0 and then PCIe 6.0 over the next 5 or so years.
https://www.businesswire.com/news/home/20190618005945/en/PCI-SIG®-Announces-Upcoming-PCI-Express®-6.0-Specification