A cheap PCie NVMe M.2 SSD will have speeds at up around 2,500MB/s and 1,500MB/s. Samsung 970 PRO NVMe drives 3,500MB/s 2700MB/s. Yes they are literally atleast 5x faster than the fastest normal SSD. Because they run off of PCie which has a max bandwidth of 80gbs at 16x. That's 10,000MB/s with a factor of 8.
SATA NVMe M.2 SSD has the same read and write speeds as a normal SSD because they still use the SATA controller which is much much Slower. Max speed for a SATA 3 controller is around 620MB/s.
PCie M.2 NVMe SSDs will only get faster. It's currently bottle-necked only by the by the speed of the current memory chips on the market today.