I realise that this isn't Mac Pro specific, but a lot of Mac Pro users also use RAID. The general comment I've seen on these forums is that with RAID 0 either disk going down takes the lot (I'm talking two disk for simplicity, of course it can be extrapolated) so you're drives are twice as likely to fail. Thinking about it, isn't it worse than that? My thoughts go along these lines; with every file striped across two disks every read and write operation will involve both disks (even though it will only be half the bytes per disk). So not only will you have the factor of two from the either disk failing issue but each disk will have more stress. A particular example scenario would be reading data from one file, processing it in some way and then writing it out to another file. If you have the first file on one disk and the second on a different disk then the drive heads will not need to move much. If both disks are combined in RAID 0 then both sets of drive heads will have to jump too and fro between the two files. (I realise that both files will often be on the same disk in a non-RAID setup but I think the point is still valid for a proportion of the time.) I am no expert, but am interested in comments from those who do know about RAID.