Hi [NAME] it seems that the old (2018) Alienware 17 R5 motherboard's 2.5-inch SATA III bay interface is incompatible with the SATA III 3D-NAND interface on the ADATA SATA SU750 which has the Realtek RTS5733DMQ DRAMless, two-channel controller. Adata Ultimate SU750 SATA SSD Review: Not Quite The Ultimate SSD - Tom's Hardware | Tom's Hardware (tomshardware.com)  There is no obvious Intel CPU 8th Gen motherboard firmware driver fix. Advocate contacting ADATA to see if there is a SATA III 3D-NAND DRAMless interface work around, or perhaps you have a bad ADATA SATA III SU750 that should be replaced under their five year warranty.  
I'm attempting to replace the sata hdd with an ssd, and it's detected in bios, but when windows boots up, it's not found.  I can swap back in the hdd and it shows up fine.  Thanks for assistance.
17 R5, doesn't recognize SATA SSD in Windows