A U. 2 SSD uses 4 PCIe lanes, which gives you a speed of 4GB/s and the SSD will have around 2500MB/s read speed. This is significantly faster than a standard M. ... 2 is an NVMe drive in a supported socket, it also uses 4 PCIe lanes giving us the 4GB/s bus and the NVMe SSDs have a read speed of 3000~3500MB/s.
