Standby vs Shutdown
When we talk about a lower power state, there are only two options we would recommend, either PC standby (incl hybrid sleep in Vista) or a complete shutdown.
When we talk about PC standby, we mean the inherent power management capabilities of windows operating systems to place monitors, hard-drives and the PC into a sleep mode after a period of inactivity. This can be achieved my modifying the windows power settings and can be managed centrally by systems administrators using group policy with admin plugins such as Energy Star’s EZGPO tool.
Shut down solutions turn the machine off completely. This can be done manually by Start > Turn Off Computer or managed centrally through PC Power Management tools such as NightWatchman from 1E. In order to turn off PC’s remotely you need to deploy power management software and cannot do this through group policy.
Why bother going the whole way?
Many organisations that we talk to have adopted a PC standby based approach. When this approach is implemented, it does compromise the delivery of the service, largely because the operating system is not getting recycled and over time just gets unhealthy.
To get the financials out of the way, machines in standby are still drawing energy but the reality is that with modern devices this is minimal. The different between off and standby is usually around 1 watt. Hardly worth the effort but then again everything counts, certainly in large environments. Anecdotally, it also appears that the longer a machine is in use, the more energy it tends to use in standby. This is true of all operating systems and we suspect it may be due to the registry growing as more and more applications are loaded. If you have the tools, as a simple test, take a new configuration and test the power in standby. Then take an identical machine that has been with an end user for a few months and do the same test. You will be amazed at the results.
A hybrid approach
The optimal way of implementing a power management solution is what we call a hybrid approach. Machines should have a policy in place to put them in in standby/sleep for the majority of the week. From and end user experience this is the best approach as the machine resumes quickly and all of their work is active on the desktop.
However, to ensure that machines remain healthy and updates are correctly applied (often requiring reboots) machines should be powered off and rebooted at least once per week.
This provides the best of both worlds. A healthy operating system and great end user experience.