Tempo SATA X4P and Mac OS X 10.4 requires the final version, 10.4.11 for tested functionality. For example, a RAID 1 set does not function under Mac OS X 10.4.6 in a Power Mac G4 Quicksilver.
Under Mac OS X 10.3 and 10.4, a volume greater than 2TB will show as a 2TB volume due to a limitation in Apple's ATA layer (just above the driver). Sonnet plans to provide a 10.4 fix in the next driver release. Under Mac OS X 10.5 and 10.6, the full capacity of the RAID volume is available.