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Easy money. You can save up to $75 or more per computer by activating system standby or hibernate features.
Screen savers generally do not save energy. In fact, certain graphics-intensive screen savers can cause the computer to burn twice as much energy, and may actually prevent a computer from entering sleep mode.
Screen savers were originally developed to prevent the permanent etching of patterns on older monochrome monitors. Modern display screens do not suffer as much from this problem, but screen savers are still used for entertainment.
If you want to use your screen saver in conjunction with monitor power management, set the screen saver "wait time" to less than the period of time after which the monitor enters sleep mode. If your screen saver appears but your monitor never enters sleep mode, your screen saver may be the culprit: try disabling it.
A popular myth holds that leaving lights, computers, and other appliances on uses less energy than turning them off and also makes them last longer. In reality, the small surge of power created when some devices are turned on is vastly smaller than the energy used by running the device when it is not needed.
Source: "Eleven Energy Myths: From Efficient Halogen Lights to Cleaning Refrigerator Coils", Lawrence Berkeley National Labs
"Modern computers are designed to handle 40,000 on-off cycles before failure, and you're not likely to approach that number during the average computer's five- to seven-year life span. In fact, IBM and Hewlett Packard encourage their own employees to turn off idle computers, and some studies indicate it would require on-off cycling every five minutes to harm a hard drive."
Source: Rocky Mountain Institute Home Energy Brief #7 Computers and Peripherals.
"The belief that frequent shutdowns are harmful persists from the days when hard disks did not automatically park their heads when shut off; frequent on-off cycling could damage such hard disks. Conventional wisdom, however, has not kept pace with the rapid technological change in the computer industry. Modern hard disks are not significantly affected by frequent shutdowns."
Source: "User Guide to Power Management for PCs and Monitors", Bruce Nordman, Lawrence Berkeley National Laboratory, January, 1997, LBNL-39466
Windows users can check power management status via the control panel: for assistance, see our detailed and illustrated manual instructions.
If your monitor screen goes dark and appears to be off after a period of inactivity, monitor power management is enabled. If, in addition to the monitor darkening, the low hum of your hard drive stops after a period of inactivity, either system standby or hibernate is probably enabled.
While problematic in early versions of Windows, today's sleep features almost never cause system crashes or keep computers from waking. Machines running Windows 2000, XP, Vista, and Mac operating systems should not experience these problems.
While they use less energy than desktops, notebook computers still burn about 20–30 watts of power. System standby and hibernate features reduce notebook power draw to 1–2 watts, so the energy savings are still very significant. Be sure to activate system standby and hibernate features in the AC power profile (which saves power when the notebook is plugged into the wall) — not just the DC power profile (which prolongs battery life.)
There are 4 basic types of computer power management, or "sleep" features on Windows PCs:
While Microsoft does ship Vista with sleep settings enabled, operating systems are usually installed by PC makers, IT departments, computer resellers, or 3rd party service providers. Windows Vista default power management settings are not typically retained.
Even if the Vista default settings are retained, you may prefer to modify the settings in order to save more energy. To maximize power savings, EPA recommends setting computers to enter system standby or hibernate after 30 to 60 minutes of inactivity. To save even more, set monitors to enter sleep mode after 5 to 20 minutes of inactivity. The lower the setting, the more energy you save.
Computer users requiring 24/7 remote access to their desktops from outside a firewall (via Remote Desktop, for instance) should utilize monitor power management features only, as it may not be possible to remotely "wake" computers from system standby or hibernate mode.
While current server software lacks such tools, there are numerous ways to centrally activate and manage these features today — many of them free. Windows Server 2008 software will include such tools.
For individuals and organizations without centralized IT departments, computer software is generally pre-configured to automatically download and apply updates shortly after resuming from system standby or hibernate.
In enterprises, there are numerous ways for network administrators to ensure that software updates are applied:
The ENERGY STAR Low Carbon IT Campaign is partnering with the Climate Savers Computing Initiative, a non-profit group that includes technology firms, energy companies and NGOs working to promote the use of more energy-efficient computers and increase the use of computer power management. Both efforts share similar goals and cooperate with each other on technical specifications and marketing through a strategic partnership.
There are three main reasons that your computer could be behaving in this manner: