I agree progress is progress, but I was expecting something a bit further from the absolute maximum bandwidth of PCIe 3.0 x4.
https://en.wikipedia.org/wiki/PCI_Express#History_and_revisions
The maximum speed of PCIe 3.0 x4 is 3.94 Gigabytes a second.
The maximum speed of PCIe 4.0 x4 is 7.88 Gigabytes a second.
PCIe 5.0 x4 which according to Wiki is going to be released in Q2 of 2019, doubles this again to 15.75 Gigabytes a second.
I was about to ask a question of what is absolute fastest a cpu could transfer data until I realized that the answer lied with the speed of the ram.
https://en.wikipedia.org/wiki/DDR4_SDRAM#Modules
This should allow us to conclude a few things ... for example.
With a PCIe 4.0 X16 device you should be unable to realize its full potential due to its maximum speed being 31.5 Gigabytes a second, but the maximum speed of a respectable DDR4-3200 ram being 25.6 Gigabytes per second.
This brings up the unexpected and actually kind of funny scenario where you would need to overclock your ram to get the full performance from a PCIe 4.0 x16 SSD adapter.
https://www.tomshardware.co.uk/aplicata-m.2-nvme-ssd-adapter,review-34022-2.html
Comes to mind from about a year ago which actually appears to saturate a PCIe 3.0 x8 at 7.88 gigabytes / second at a queue depth of 4 with 10% or so loss to overhead when reading.
Is this the correct way to think about this?