I know i'm a bit late to the part but just to add to my experience with using non 'RAID' drives in a RAID array. Hard drives classed as RAID drives have different firmware which allows the RAID controller to talk to and control the drive directly. Normal desktop drives dont talk directly to the RAID controller and if they detect a read/write problem and try to correct it the RAID controller can interpret this delay as a failed drive and fail the array. I know this from personal experience when running a 6 drive RAID array on an Adaptec controller. I'm glad you didnt buy an Adaptec card as their support is shocking.