I'm not asking how RAID works, what I'm interested in is why people use it. Let me explain. RAID 0 is fine, you use it for performance and to make a larger file-system so to consolidate all available space. The alternative of course is JBOD which has the advantage of not requiring identical disks. RAID 5 is fine, you get performance and redundancy and for 'real-time' updating applications it's probably mandatory. However, IMHO RAID 1 is nearly pointless. Why? Well, it's a substitute for RAID 5 in many situations but given disk costs these days then the extra paid for a parity disk is worth it in most cases I'd suggest. For all systems where files are largely static then IMO RAID 1 is NOT a good idea. Sure, it guards against disk failure but what it doesn't protect against are those kinds of problems which in my experience occur far more frequently than disk failures: software crashes causing file corruption and far more likely the "whoops, didn't mean to delete that" syndrome. In HTPC applications we're talking about huge files but not ones that change once they're created. In this application I think using simple disks and a timed backup program, like Second Copy I use or one of many other such, provides not only protection against disk failure but also most of the 'accidents' which can occur that RAID 1 doesn't protect against. I put this thought up for those considering using RAID 1 as something to consider. Simply because your mobo can support RAID 1 doesn't mean it's a good idea to use it .. IMHO, of course.