- 20 MB/sec is the max data rate for Fast/Wide SCSI- 40 MB/sec is the max combined data rate for 2 ch of Fast/Wide SCSI- 40 MB/sec is the max data rate for 1 ch of Ultra SCSI (Fast-20)- 80 MB/sec is the max combined data rate for 2 ch of Ultra SCSI (Fast-20)Due to overhead involved, the actual maximum data rates are probably closer to 18 MB/sec, 36 MB/sec and 72 MB/sec, respectively. EPCI-DC cards in the SCSI64 Kit are set to Fast/Wide SCSI (20 MB/sec per channel) at the factory. The sustained data transfer rate is different than the maximum transfer rate as described above. Sustained rates are usually less and are very dependent upon the model of the drive.