Yeah, RAID-0 isn't really 'R'.
Early SCSI-1 hard drives are slow enough that you would see an improvement moving to RAID - but you'd see a bigger improvement by putting a later-model 7200 RPM (or, if you're nuts like me, 10K RPM,) drive on. Put a single drive on that is significantly faster than the bus, and you'll be good.
(Old parallel SCSI, like parallel ATA, is a "shared bus". Its maximum speed is shared among all devices on the cable. So if you put two "fast" hard drives on an old Mac's 5 MB/s SCSI bus, you're wasting it.)
Early SCSI-1 hard drives are slow enough that you would see an improvement moving to RAID - but you'd see a bigger improvement by putting a later-model 7200 RPM (or, if you're nuts like me, 10K RPM,) drive on. Put a single drive on that is significantly faster than the bus, and you'll be good.
(Old parallel SCSI, like parallel ATA, is a "shared bus". Its maximum speed is shared among all devices on the cable. So if you put two "fast" hard drives on an old Mac's 5 MB/s SCSI bus, you're wasting it.)