AMD barely announced its next-gen Ryzen 3000 series and new X570 boards touting the first PCIe 4.0 specification, so PCI-SIG decided to announce the next-generation PCIe 5.0 specification doubling the bandwidth from the already next-gen PCIe 4.0 standard.
PCIe 4.0 arrives with X570 boards and will be capable of 64GB/sec on a x16 slot, while PCIe 5.0 will come through and double that up to 128GB on a new PCIe 5.0 x16 slot -- all the while PCIe 3.0 delivers 32GB/sec on a full x16 slot. We won't see massive advancements in the graphics card side of things for gamers from this massive increase in bandwidth, but NVMe/Optane SSDs will get a HUGE kick in the ass in terms of bandwidth.
We are already seeing up to 4GB/sec on a PCIe 3.0-based M.2 SSD at x4, so imagine this doubling to up to 8GB/sec on PCIe 4.0 and a huge 16GB/sec on PCIe 5.0 x4. Yeah, 16GB/sec from your SSD. If you thought the PCIe 4.0-based NVMe SSD inside of the PS5 (that's what I started hearing from sources at Computex) then the PC is going to take things to the next level in the coming years with PCIe 4.0 and then PCIe 5.0.
Why are things advancing to PCIe 5.0 so quickly? That would be because of teh huge delays of PCIe 4.0 rolling out, it should've been here years ago and is only arriving in the second half of 2019. We could see PCIe 5.0 roll out in the coming years on next-gen Intel and AMD platforms, paving the way for even faster storage and much more bandwidth over full x16 slots for next-generation GPUs.