Mac OS X: Apple Fibre Channel and SCSI PCI Card Can Prevent Deep Sleep

If the Apple Fibre Channel PCI card or other Apple SCSI PCI cards are installed in a computer, the computer cannot enter deep sleep mode.
This article has been archived and is no longer updated by Apple.

When the Apple Fibre Channel PCI card or another SCSI PCI card is installed in a Power Mac G5, Power Mac G4, or Xserve, the system does not sleep. Therefore, your system will not go into low-power mode during long periods of inactivity. Because the Power Mac G5, Power Mac G4 or Xserve is unable to sleep, the fans may appear to run excessively.


This is expected behavior. The fact that the system does not sleep causes no harm to the system or its components.
  1. Open System Preferences.
  2. Select Energy Saver.
  3. Move the computer sleep slider to "Never", so that the computer does not attempt to sleep.

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Last Modified: Oct 10, 2016

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