PolGZ@reddit
One nvme will only use at most 4x lanes. It won't use x8 nor x16.
So on PCIE 2.0, you'll get max (theoretical) 2GB/s. More likely a bit less on the actual nvme performance, around 1.5-6 GB/s or 1500-1600 MB/s. That's around >3 times what a regular 2.5" SSD will do.