NVMe drives are much faster than their SATA equals because they screw straight into your motherboard. Gen 3.0 models top out at 3,500 MB/s sequential, and Gen 4.0 are able to push upwards of 7,000 MB/s depending on the choice of controller and DRAM. Gen 3.0 drives are backward compatible with 4x4 M.2 ports, however, you won't get the same speeds out of Gen 4 drives in 3x4.