There are key differences between Windows XP and Windows Vista where power-management functionality is concerned. One of these differences concerns how the Windows Vista power-management feature works for the HD audio controller and for any child devices. For example, assume that you decide to disable an HD audio controller’s Wake on Ring feature on a Windows Vista-based computer by disabling the Allow this Device to wake the Computer option. In this situation, the Wake on Ring feature still wakes the computer from sleep and from hibernation.