ArcadeGuy posted...My board has M.2 slot and I saw you can buy PCI-E adapters as well.
Technically speaking, no. Not sure what board you have, but assuming it's a Z370 board (or anything non X really, for Intel anyway) the PCI-E 1x, NVMe slots, and (usually part of) the 4x slot all share the same 4x PCH bus, as well as all the other low bandwith board addons (Sound, USB, network, etc). The 16x slots of course share with each other, so if you use the other 16x slot you'll only get 8x for each slot. Shouldn't impact anything really, but worth pointing out. For 1 NVMe drive, it will be fine and you shouldn't notice any speed difference. For 2 or more, it depends on how fast they are, and what you're doing with them. IE, an 960 Evo or Pro can almost saturate the 4x bus (not that you're likely to do this is real time usage) but many cheaper ones wont. If you're wanting to raid the drives, they'll need to be on the same sets of buses, as the PCH doesn't intermingle.
TL;DR: 1 drive should do you fine, doesn't really matter where you put it.
It's not the fall that kills you, it's the rapid deceleration.....
*shoves next poster off a cliff*