Latency is not related to CPU power, until the DSP load starts creeping up. For just low latency tracking, a 486 is perfectly capable.
DSP based systems struggled a lot with IO in the late 90s until faster SATA drives became ubiquitous. Lots of them used SCSI or exotic hardware cards to deal with large track counts.
It did have a SCSI drive, but in 1999 I did not consider that "exotic", having been using them on various Unix workstations for more than a decade before that.