There is a known issue with Adaptec PowerDomain U160 SCSI cards and the Apple Power Macintosh G4 systems (1 Ghz, 933 Mhz, 867 Mhz, 800 MHz, 733MHz, 667MHz, 533MHz and 466MHz) with 133 MHz system bus. These G4s with an Adaptec PowerDomain U160 SCSI card installed will not go into Deep Sleep. There is currently no work around for this issue in Mac OS 9 (under Mac OS X these cards fully support Deep Sleep on all compatible systems), for details on each SCSI Card please read the ASK article on G4 Deep Sleep Issues.