The part number from the vendor is irrelevant, is really difficult to understand part numbers(vendors sometimes can get them mixed). Despite the part numbers, The real difference is between the Samsung EVO PRO and the Samsung EVO.
Both the 960 Pro and 960 EVO SSDs use the M.2 2280 form factor, NVMe, a Gen.2 PCIe x4 interface and Samsung V-NAND.
Samsung rate the 960 Pro at 3500 MB/s reading, and 2100 MB/s writing, which makes the SSD one of the fastest options available. As a comparison, the 950 Pro from 2015 clocks in at 2500 MB/s reading, and 1500 MB/s writing. The 960 Pro also manages 440,00 and 360,00 IOPS, reading and writing.
The speedy SSD is backed up by a 5 year warranty, or up to a massive 1.2 Petabytes written for the 2TB capacity. The 1TB 960 Pro is good for 800 TBW and the 512GB does 400 TBW.
The 960 Pro is available in 512GB, 1TB, and 2TB capacities - the latter the only consumer SSD available so large. And forget about 128GB or 256GB drives.
The 2TB will set you back around $1700, while the 1TB costs $900, and the 512GB is $450.
The 960 EVO plugs one gap in the lineup, with a 250GB model, as well as 500GB and 1TB. The EVO costs $190 for 250GB, $350 for 500GB, and around $680 for 1TB.
It’s rated at up to 3200 MB/s reading, and from 1900 MB/s down to 1500 MB/s writing, depending on the capacity.
http://www.samsung.com/semiconductor/minisite/ssd/product/consumer/ssd960.html
https://www.gizmodo.com.au/2016/11/hands-on-samsung-960-pro-and-960-evo/