raid 0 = striping two drives, cutting data into two equal parts and putting them on two seperate drives & they act like one
raid 1 = mirroring two drives, cloning data into two parts and putting them on two seperate disks
raid 0 +1 = stripes the drives first, then mirrors it onto two other drives
so 4 Hard drives needed
and im not familiar with the nForce4 4x, only ultras and SLIs