I run two 74 GB raptors in a RAID 1, and get 125MB/s on HD tach (slight speed penalty for the RAID1 setup). I upgraded (and stil have in the same machine) 4 maxtor ata133 80GB drives in RAID 0,1 and the RAID1 setup with the raptors is faster. If you are looking for speed and performance, go with the raptors. If you are concerened with relaibility, get 4 and go for the RAID 0,1 setup. If one dies, just plug a new one in to take its place! A 5 year warrentee is great, but how often do hard drives really die anyway? In my experience, not really that often and usually when they get really old anyway and its just plain time to upgrade because technology has passed them by. I have computers running in my office that were used 8 hours a day since 1998 and even those dinasaurs are still kicking.