decameron118 :
Dunlop0078 :
The 850 EVO uses the SATA interface it's speeds will be same regardless of if you get the SATA or M.2 version. The 850 evo's M.2 version even though it is plugged in via M.2 still uses the SATA interface therefore it is limited to SATA 3 speeds.
If you want an M.2 drive that will actually take advantage of the extra bandwidth of the pcie interface then you need to look at something like the 960 evo.
How about mSATA? it seems cheaper than m.2 ssd.of same capacity Is there a crucial difference?
There is no difference between any of the 850 evo's in terms of performance, I don't know how many more times we can say this. I would not get the mSATA version, that is a dying interface future motherboards may not even have.