Most new computer monitors comply with U.S. government Energy Star standards that require them to power down when the sync signal is turned off. When used on an Energy Star aware Macintosh (any of the Quadra or later models), Sleeper can turn this video signal off to power down the monitor.
Since the monitor is typically the largest single power consumer in a computer system, turning it off can save quite a bit of electricity, so it's beneficial to use this feature when you can. The only drawback is that when you begin using your Mac again, it will take a few seconds for the monitor to power back up, so you don't want the Energy Star feature activating too early. The best strategy is to have Sleeper's screen saver dim the screen after a few minutes of inactivity, and then have the Energy Star feature power down the monitor after 15 to 30 minutes, when you're obviously away for an extended period, not just getting another cup of coffee.
 
Setup
To turn on Sleeper's Energy Star feature, click on the Energy Star tab in the Sleeper control panel, and turn on the Suspend monitor when idle or Power off monitor when idle checkboxes. Use the Delay sliders to set the number of minutes your mouse and keyboard should be idle before Sleeper turns off the monitor. If you want to set a delay higher or lower than the slider allows, option-click on the slider.
The difference between suspend and off varies depending upon both the Macintosh model and the monitor. For Macs prior to the first PCI PowerMacs (the PowerMac 7200, 7500, 8500, and 9500), these two modes are the same. In later models, the behavior depends upon the type of monitor you have. Generally, suspend mode uses slightly more power, but the monitor will turn back on faster than it will when turned completely off.
Enabling each of these checkboxes in turn and using the hotkey to power off the monitor will allow you to test whether there's a difference on your configuration. Note that you must leave the monitor in Energy Star mode for a minute or so before you can accurately judge it's recovery time when it turns back on.
The Don't wake up for mouse movement checkbox tells Sleeper not to turn the monitor back on until a key or mouse button is pressed, rather than whenever the mouse is moved. This prevents your monitor from waking up when the mouse is bumped.
Additional Notes
If you don’t have an Energy Star compliant monitor, the picture may look very strange when Sleeper turns the sync signal off. In this case, the Energy Star feature will not offer any energy savings.
Because Apple and graphics board manufacturers have not made programming information available, there may be some systems on which Sleeper's Energy Star functions will not work. This includes Apple's PowerMac AV Video Card, which is used in the PowerMac 7100AV and 8100AV systems, and Macintoshes that use the "Screen" control panel, namely the Color Classic and LC 5XX series. We will update Sleeper as we are given more information about these and any other problem graphics cards.
