I am considering buying the XPS 8900, but I need a computer that supports RAID 1 mirroring because I store some critical files and I prefer RAID 1 over typical network/USB backup processes. (I actually do both just because I am paranoid about losing my files)

I noticed the Spec's given on the dell forum  (http://en.community.dell.com/support-forums/desktop/f/3514/t/19654880) lists "One M.2 SSD with RAID 0 Stripe/1 Mirror".

I am confused on how you can have 1 M.2 SSD with RAID 1 Mirror and 6 SATA-III ports. Would the M.2 drive mirror a SATA drive, if so this seems really inefficient.

Will the XPS 8900 support RAID 1 without using the "software RAID" built into Windows? If not, does anyone have a suggestion of a Desktop PC that I look at?