Since the arrival of the XP941 last year, and later on the SM951 NVMe, we have been waiting for a more affordable mainstream version. Recently Samsung delivered just that with its new SSD 950 Pro Series. Made exclusively in the M.2 2280 form factor, the new 950 series comes in either 256GB or 512GB capacities -- priced at $190 ($0.74/GB) and $350 ($0.68/GB), respectively.
Featuring the same UBX 3-core controller found in the SM951, the 950 Pro receives native PCIe and NVMe support. Surprisingly, the SM951-NVMe was paired with Samsung's 16nm 64Gbit MLC NAND flash where as the mainstream 850 Pro series received the more advanced Samsung 3D V-NAND (32-layer 86Gbit MLC) flash.
This is where the 950 Pro has been upgraded, as the UBX controller has been paired with Samsung's 3D V-NAND (32-layer 128Gbit MLC).
Therefore technically there is nothing "new" about the 950 Pro series, it just combines all the best bits that Samsung has brought to market so far.