A:Answer Since many have answered this question incorrectly, I'll answer it with information straight from MSI.
There are 3 m.2 slots. 2 are NVME\SATA capable, the other is only SATA. So, basically 2 are the 'fast' ones, and the SATA one will be 'slower.'
When taking off the back... the 2 NVME capable are next to each other and the SATA capable is off to the side.
https://www.msi.com/Laptop/GS75-Stealth-8SX/Specification