Macintosh bootable volumes are supported on the internal 2-port PCI card (part number TSATA) but are not supported on any of the other SATA cards at this time.
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.