I'm building up a server using storage spaces on Server 2012 R2. Tried adding a SSD tier today using and Orico PRS2 set to AHCI mode with two M.2 drives. Seemed to work though haven't conducted any performance testing yet. The server will mostly be processing large files between 500Mb and 20GB. Has anyone tried using these Asus adapters with FOUR slots? https://www.asus.com/au/Motherboard-Accessory/HYPER-M-2-X16-CARD/ Can anyone confirm if they will support AHCI mode so as to present the raw disks to the OS? Also, can anyone explain how Storage Spaces works on 2012 R2 vs S2D in 2016? I think the former is at file level and the later is block level. Does this mean the former would only ever store a file in a single SSD no matter how many are in the server, and thus limit throughput performance to a max of one SSD? If the SSDs are all 120GB, does this also mean that no file can ever be held in the cache tier if it's larger than 120GB, or if the SSD is already partly full?