Check out the excellent post
here detailing the GUIDs involved when using the
powercfg.exe command in Vista.
The dirty little secret is that
powercfg.exe is also pretty much the only way to control power management inside a Windows Server 2008 Core server.
At minimum, I usually set these values on my Core VMs/Core Servers, inside a batch file, which is primarily a cut and paste from some of Richard Smith's post:
REM sets the power configuration to High Performance
powercfg -setactive 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c
REM turns hibernation off
powercfg -hibernate OFF
REM set the absentia power scheme (the scheme used when no one is logged in)
powercfg -setabsentia 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c
Note: Many people might wonder why I am setting power management settings on a virtual machine, but I tend to use VMWare Workstation 6.0 and report battery status, which in turn enables power management items inside Server 2008 and Server Core 2008.
