Hiya, silkeJust to throw some sand in the mix ;-) RAID 1.5 is a MIRROR/STRIPE configuration that uses only two drives. DFI LANParty MB's have the controller onboard. Tom's Hardware reviewed it: http://www.tomshardware.com/storage/20030620/index.html The benchmarks so a slight benefit with 64+block reads and easier on the CPU. It has a slight downside (negligible for home users), but working with large files on disk-I/O intensive app like Poser, it's great.