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Windows battery life has rocketed forward in the last few years thanks to new processors from Intel that provide strong performance on a fraction of the power previously required. Even inexpensive laptops can often hit five or six hours, and models specifically designed for portability frequently exceed eight.
Yet these improvements have made the way you use your PC more relevant to endurance than ever before. Modern processors do everything they can to reign themselves back to a low-power state quickly, but changing settings or even your usage can defeat all the good work Intel has done. Here’s what you must know to quickly craft an effective power plan.
A “power plan” is simply a collection of settings in Windows that determine how certain features operate. Plans are available on any Windows PC by doing a desktop search for “power plan” and selecting “choose a power plan,” but they’re more important and easier to find on systems with a battery. Any Windows rig that has a battery will also have a battery icon in the system tray that can be used to access power plan settings.
By default a Windows system will offer three default power plan options; maximum performance, balanced and power saver. Manufacturers occasionally add their own plans, as well. You can switch between plans at any time, change them however you’d like, and create new plans by clicking the “Create a power plan” link on the left side of the Power Options window.
There are ways to improve battery life besides your Windows power plan and some laptop functions, like display brightness control, will temporarily over-ride a plan. That is important to remember. You can ruin the effectiveness of a power plan by changing settings manually. Your Windows power plan might also fail to work if it’s overridden by another application. This often occurs when a PC builder creates their own proprietary power plan software, a redundancy that often confuses users.
A plan will only work if it’s in charge. Manually changing settings, or using a third-party power tool to override it, will invalidate the plan’s results.
Automatic Display Dimming, Sleep and Display Brightness
These three settings form the core of every Windows Power Plan. They’re easy to understand, but that doesn’t mean they should be ignored or don’t have an impact. You can play around with the additional settings all you want, but you won’t extend battery life until you come to terms with these three core options.
Display dimming and sleep determine how long your notebook is allowed to sit at idle before either occurs. A default “balanced” power plan will usually dim the display after 3 minutes, allow the display to stay on for ten minutes, and then stay on for another five minutes before it goes into sleep. Both settings should be as aggressive as you can tolerate, if extending battery life is your goal. Every minute your computer is at sleep instead of idle is (almost) a minute of battery life added. That wasn’t always true five years, but a modern Windows notebook can last over a week in sleep mode.
Of course, decreasing the time your notebook is idle before it goes into sleep can be inconvenient, if you’re reading or watching media. For this reason I suggest setting up at least two power plans; one for active use, which should have a very short sleep timer, and one for media, which has a long sleep timer. Use the active plan as your default and switch over to the media plan only when needed.
Display brightness is important, too. In my experience reviewing laptops, I’ve found that modern notebook displays will draw 1 to 2 Watts more at maximum brightness than they do at half. That may not seem like much, but many laptops eat just 10 Watts at idle, so a consistent 1 to 2 Watt difference translates to a 10 to 20% decrease in battery life. The relative importance of display brightness decreases as the load on a system increases, though, so don’t fret over it when using demanding apps.
Dimming a display is a great way to save some power but it can be fussy in practice. The brightness you need to use your notebook is different when it’s in a dark room than when it’s in full sunlight. Windows can help you solve this by automatically adjusting brightness (if your notebook has a webcam).
To access this option click “Change advanced power settings” while in your Windows power plan. In the Power Options window, scroll down until you reach the Display section. Expand it and then open “Enabled adaptive brightness.” You’ll see the option to turn it on or off. Adaptive brightness can lengthen battery life, but some users find that it’s too dim, and there’s no way to adjust exactly how dim the display becomes. Try it out and see if you can tolerate it.
If you adjust this setting, but find it has no effect, try right-clicking on the desktop and then opening Intel’s Graphics Properties (if available). Go to the power section and look for the “display power saving technology” option. This can cause brightness to change even after you’ve disabled the adaptive brightness feature in your Windows Power Plan, so turn it off.
Advanced Sleep Settings
The sleep timer that’s displayed when you adjust your power plan is not the only sleep-related setting you can adjust. The advanced Power Options window provides three additional options; hybrid sleep, hibernate and allow wake timers. Hybrid sleep is intended for desktops, so only the latter pair is relevant to battery life.
Hibernate dumps your system RAM to your hard drive and then shuts down your computer, which drastically cuts (but does not completely eliminate) power draw. Even aging laptops can last weeks in hibernation. Also, your computer’s state is already saved to your hard disk, so you don’t run the risk of losing data when the battery gives out (a common problem with sleep). Hibernate is usually turned on by default and you should absolutely turn it on if you find it’s not enabled. I recommend setting hibernate to activate after the computer has been asleep for fifteen minutes.
Sleep timers are system events that bring your computer out of sleep when they activate. I recommend turning this off, unless you know of a specific program you want to wake your laptop from sleep. This usually doesn’t save much power, but it can save you from the unpleasant surprise of a dead battery because an errant program kept your notebook up all night.
Processor Power Management
While the display’s brightness is important to the endurance of a system at or near idle, it’s not important at load. A notebook that’s running a demanding program can easily demand two or three times more power than it would at idle, and almost all of that extra juice is used by the CPU (unless your notebook has a discrete GPU, which also consumes Watts).
You might be able to adjust power draw by expanding the “Processor power management” tree in the Power Options menu. You’ll then see the option to adjust the minimum and maximum processor state along with the cooling policy. There’s no reason not to have the minimum at 0%, and the cooling policy settings rarely work, so the maximum processor state is all you need to worry about.
Maximum processor state is expressed as a percentage and can be adjusted to behave differently on battery than it does on power. Unfortunately, expressing this figure as a percentage is a bit deceptive. It implies, for example, that a 2 GHz system has its maximum power state reduced to 10% and will run at 200 MHz as a result. That, of course, isn’t what happens. Every processor supports a variety of preset power states and it can only change its performance to power state that most closely mimics the percentage you set in Windows.
Another problem with this setting is its lack of reliability. Many systems ignore maximum power state at their leisure and will draw exactly the same power and report exactly the same benchmark scores with the power state at 20%, 50% and 100%. As bizarre as it may seem, I suggest knocking maximum power state down to 0% while on battery. Even if the setting has an effect, your processor’s minimum power state will not be so low that it inhibits normal use.
What Doesn’t Matter
Processor power management is finicky, but it’s far from the least functional aspect of the Power Options menu. There’s actually a number of settings that have no meaningful impact, even when they work correctly. Irrelevant settings include those listed under; hard disk, desktop background settings, wireless adapter settings, USB settings, power buttons and lid, and multimedia settings.
Some of these, like desktop background, have laughably little to do with power draw. Whether or not your computer’s background changes every minute, three minutes or ten minutes is completely irrelevant.
Other options, like changing the speed with which your hard drive turns off, are theoretically useful, but the component in question uses so little power that its impact on battery life is difficult to notice outside of carefully constructed, instrumented tests. A mechanical hard drive, for example, demands between one and three Watts while active – but spends the vast majority of its time at idle, consuming just a few tenths of a Watt.
You could spend weeks testing these settings with a wattmeter and a stopwatch and never obtain a quarter of the gains you’ll receive by decreasing the brightness of your display when it doesn’t need to be at its maximum. Don’t waste your time; focus on the fundamentals.
Savings Are Limited
There are limits to what a Windows power plan can do. It’s a cruel irony that laptops with a small battery will always see less benefit than those with a large battery. There’s simply not as much power to work with. With that said, an appropriate power plan can make a positive impact; at best I’ve seen changing a plan tack an hour and a half of web browsing endurance, increasing the system’s endurance from five hours to six and a half.
How much additional battery life have you extracted from a system simply by changing its power plan? Let us know in the comments!