I agree with DGroves regarding the M.2 drive. If it's not visible in the BIOS when placed in either PCI slot (3), 4 or 5 then the M.2 PCI adapter card is likely the culprit. Even I fell for this trap with my SM951 M.2 AHCI drive. I initially bought a cheap PCI adapter card on eBay and couldn't even see the drive visible in the BIOS. I then bought an ASUS M.2 PCI adapter card and the drive works perfectly (and installed very easily, after initializing the drive in Drive Manager).