Hi [NAME] welcome to this free user to user Alienware laptop discussion forum.  Support for Alienware m15 R6, Storage.  Alienware m15 R6 BIOS has acknowledged installation of the new M.2 drive card in the system board (aka motherboard). Now the windows operating system needs to assign partition letter and format the new M.2 drive card with a partition for data storage. Please watch following video.   
I recently purchased an additional SSD for my m15 R6 laptop and it will not recognize the drive. I can see it in BIOS settings but not when I open windows explorer. Is this computer compatible with newer PCIe 4.0?
m15 R6, compatible with a PCIe 4.0 SSD?