The XP User's Guide to Windows Vista, Part 7: Power Management and Power Plans

1. The Power Options Section of the Control Panel

As with Windows XP, the place to manage the system's power-management functions in Vista is in the Control Panel, under Power Options.  What you'll find, though, is that the original dialog boxes have been replaced with something completely different.

By default Vista comes pre-packaged with three power plans, or power management profiles.  In XP they were called "power schemes", and there were several more of them, but Vista has slimmed them down to three basic profiles: balanced, power saver, and high performance.

• Balanced: This profile provides the best balance between power savings and performance.  Most notebook users will want to select this one when they're unplugged.
• Power saver: This profile allows for the highest level of energy savings -- the most aggressive CPU throttling, the quickest hard-drive timeout, and so on.  People who are on a notebook and away from a power source for a fairly long amount of time will want to choose this while they're traveling.
• High performance: This is the best plan for a plugged-in computer, since it still retains some energy-saving functions but for the most part lets things run full speed.

To select a power plan, simply click on the radio button next to its name; the changes take affect immediately.  For a desktop, High performance works fine since it already has a number of power-conservation strategies set up that kick in when you step away from the keyboard for an extended period of time.

Yu can always customize the plans or create an entirely new power plan of your own, if you want to set up something that's closer to your needs.

1.1.Changing a Power Plan

If you're like me, you're going to want to know what the settings for those power plans are, and how to adjust them.  To get a better look at the settings for a given plan, click Change plan settings next to the plan in question.  When you do this, you'll see some additional details about the plan.

Obviously this isn't everything, just some of the most commonly-changed stuff.  If you want to dig deeper, click on Change advanced power settings.  That'll bring up a more detailed menu of options that you can use to really get tweaking.

Note that if you're on a notebook computer, the options you see here may be slightly different:

1.2. Advanced Power Settings

The Advanced Power Settings menu is actually the closest thing you'll see to the old XP power settings menu, but it's also changed a great deal -- mostly in terms of what options are available.

The drop-down at the top lets you choose which power plan you're editing; by default, it'll be whatever one you were working with when you clicked Change advanced power settings.

• Additional settings: Require a password on wakeup: This lets you choose whether or not you need to supply a password to the system after it comes up out of hibernation.
• Hard Disk: Turn off hard disk after __ minutes: This controls how long the hard disk(s) will idle before spinning down.
• Wireless adapter settings: Controls the level of power savings for wireless adapters (if any) installed in the computer.  Note that the more power savings you use with a wireless adapter, the weaker the signal or throughput might be.
• Power buttons and lid: Controls the behavior of the power button and the start menu power button.
• PCI Express | Link State Power Management: Governs the power management state for the PCI Express bus (if one is present in your computer).  The more the power savings, the greater the impact on performance.
• Processor power management: This lets you control how much to throttle the CPU, which is mainly used when you're on a notebook PC but can also be used with a desktop that has intelligent processor power management for reduced power consumption.  There does seem to be a lower limit to how effective the throttling is, but I have not yet determined what it is.  (But in short, no, you can't get 200 hours of battery life by setting both minimum and maximum CPU to 1%.)
• Search and Indexing: Controls how aggressively the computer performs indexing operations for the search engine.
• Sleep: This controls how long the system idles before going to sleep, or before hibernating completely.
• Display: This controls how long the display remains on when the system is idle.  Adaptive display will lengthen the wait time before turning off the display if the system is woken up often.
• Multimedia settings: Controls how media sharing affects power management -- for instance, you can allow the system to keep from idling to sleep mode so that remote multimedia users aren't disconnected.
• Battery: Controls the actions taken when the battery level reaches certain markers, and what those markers are (i.e., if the "critical battery level" marker is 10% of available power or as little as 3%).

1.3. Additional Options

The left-hand panel of the Power Options window has a series of contextual options you can click to make other changes.

If you click Require a password on wakeup or Choose what the power button does, you'll be brought to a menu that changes these settings for all power plans.

Note that by default the "Password protection on wakeup" option is greyed out; you'll need to click on the "Change settings that are currently unavailable" (UAC) link to edit that.

The other options simply take you to the Change plan settings menu for the currently-selected power plan.

2. Power Settings for Notebooks

If you're on a notebook computer, the menu for editing the settings for a given power plan will be slightly different.

Note how there's now settings for how the system will behave on both battery power and wall current.

2.1. Advanced Power Settings for Notebooks

Likewise, in the advanced settings, you'll see two options for each entry: one for how the system behaves on wall current, and another for how it behaves on battery power.

You may also see some setting entries that weren't there before, but this will vary from system to system depending on what you can support.

2.2. The Notebook System Tray Power Icon

If you're on a notebook computer, you'll see the power icon in the system tray.  Hover over it and you'll see the current level of battery life and what power plan you're using.

If you click on the icon, you'll get a pop-up that will let you choose the power plan on the fly, and give you links to the Power Options menu and Mobiliy Center.

(The Mobility Center is something I'll be exploring in a separate article as well.)

Note that the power level in the battery icon has a few more gradations than it did before, so it gives a slightly more accurate at-a-glance view of the battery level than the XP icon did.