Hi [NAME] thank you for sharing test results. In summary: Both PCIe SSD slots work, system board is not damaged. SSD card #1 is dead and cannot be recovered. SSD card #2 is good and functions as a single SSD OS (C:) boot drive, hopefully with everything intact.  Dual SSD RAID_0 is unreliable and an ultrafast single SSD is advocated as your OS (C:) boot drive.  Support for Alienware x17 R1 Storage says one of the slots supports M.2 2280 PCIe Gen4 x4 NVMe (could be slot SSD-1). Storage Devices: One PCIe4 and one PCIe3, Here. The Crucial System Advisor database has the the most recent tested storage options: Alienware Alienware x17 R1 | Memory RAM & SSD Upgrades | Crucial.com.  We recommend OS (C:) boot drive should be a single ultrafast 2TB M.2 2280 PCIe Gen4 x4 NVMe with 6600MB/s Read, 5000MB/s Write, or similar. Use Macrium Reflect Free to clone (copy) your existing 1TB OS (C:) boot drive onto your new ultrafast 2TB NVMe SSD. Clone (copy) should have inherited the modern GPT partition format so that BIOS enables UEFI boot list option. The OS (C:) boot drive should have large capacity so there is large empty space to allow intensive graphic games or applications to quickly unpack and use temporary files. Store personal files, etc. on DATA (D:) drive. 
Hi, i have an alienware x17 R1 with 2TB raid 0 ssd. i recently had a problem with my alienware were i had « no boot device found » because of some error on my ssd. In order to fix that i tried to reset my pc to factory settings but i couldn’t succed so i ended up removing raid on my ssd from the bios. From there i tried to boot on some usb key that had windows on it but had error 0x80070057 and couldn’t remove any partition or create any. (i still had 2TO displayed on the windows recovery and on diskpart aswell at that point). from there i used the command prompt and selected the main disk that had 2TO displayed and cleaned it with diskpart. I rebooted my pc and could install windows but now i only have 1TO displayed instead of 2TO. Only one ssd is showing no matter what software (same in the BIOS) i use and even when i try to reset my pc again. i tried to change my ssd position to see if they had a problem (unplung one and let the other, switch their position). And it seems like both of them have 1TO with same things on it but i can’t have my 2TO back and can’t recreate the raid again. i probably messed up by removing the raid thing in the bios and i’m getting out of ideas on how i could fix that so if anyone has a similar experience or some clues on how to fix this please help me. If you need more informations please let me know. Thank you for reading and for help
x17 R1, SSD raid 0 error