speed is in the transfer not the RPMs of the drive. That is just access. SCSI's major use is within RAID arrays where you can have a RAID5 array with 14 drives running at 15000RPM It offers amazing access speeds and very fast write. but you could never afford that for personal use. That is why companies have to spend hundreds of thousands on servers.
Also, the controller is based on the interface speed you want. There are scsi 320, 160, and older. the number means the data thoughput. IE 320 MB/sec 160 MB/sec Max Burst
Also, the controller is based on the interface speed you want. There are scsi 320, 160, and older. the number means the data thoughput. IE 320 MB/sec 160 MB/sec Max Burst