RAID 1 is drive mirroring and is not used to get high transfer rates. RAID 0, on the other hand, is drive striping that would increse transfer rates. Also, no drive can even come close to breaking ATA 66 so it does not make that much difference. Just make sure that you put the drives on seperate IDE channels. Also, these drives do not have the highest STR available since they are a generation old, but they do have an unmatched seek time that makes up for the lack in STR imo. That is why I chose mine.