Roger W. Norman wrote:

You can see what my experience tells me. With audio ATA100 drives work well
enough and you're less inhibited by bussing problems than with SATA (they
each require their own bus), but still, I haven't seen anything that
superscedes SCSI for an all out performance machine.

SCSI drives are faster (and more expensive) than ATA drives, with the notable exception of the WD Raptor series (which are basically SCSI-class drives with SATA interfaces.

The caveat with SCSI for audio machines is that many of the host adapters are serious bus hogs and can overwhelm your PCI bandwidth to the point where audio performance takes a hit. Modern x86 chipsets have their PATA or SATA ports hangiung directly off the southbridge and therefore not sharing PCI bus bandwidth. Server chipsets typically have multiple PCI buses so the disk controller(s) can be separated from the other I/O but many server chipsets don't handle low latency audio as well as the desktop chipsets.