The M6e Black Edition is an PCIe 2.0 x2 M.2 interface SSD (just like the M6e before it) based on a Marvell PCIe to flash controller (88SS9183) with 19nm MLC NAND flash modules by Toshiba (2nd gen A19) and currently available in 128, 256 and 512GB capacities. Unfortunately as expected although the 512GB variant offers a very good write performance of up to 625MB/s that number drops to 580MB/s for the 256GB model and even less at 335MB/s for the 128GB model which we have here today.

Link