Greg Shultz examines Windows 8.1's power settings to help you get the most out of a single laptop battery charge.
A friend of mine who has been an adamant Windows 7 user recently purchased a Dell laptop running Window 8.1. He had heard that of all the recent versions of desktop Windows, Windows 8 was one of the most battery-friendly operating systems of all time (his terminology). As such, he decided that he was going to spend the first week with his new laptop fine-tuning the power settings to squeeze as much battery life as possible out of a single charge.
He asked if I could give him some pointers and I readily accepted, as long as he provided the refreshments. So, over the course of about five days, we spent several hours at a time tweaking the various power settings, testing them, and then running the system to see how long it would run on a single charge. When we got up to x.x hours on a single charge, we decided that we had done the best that we could.
While we were experimenting and testing the various settings, I decided to write an article on the topic so that other like-minded individuals would have a foundation for tweaking Windows 8.1's power settings.
Note: You'll notice that I didn't mention any details about the laptop we were working with, nor have I specified the number of hours that we got on a single charge. The reason for this is that I want to focus on the adjustments that you can make and not spark a "my laptop is better than your laptop" type of debate here. Besides, your mileage will vary widely, as there are so many factors that can come into play, such as different hardware components, manufacturer battery tweaks, and the type of software that you run. So, it will be to your advantage to spend time getting the most out of your laptop battery rather than worrying about how much time others are getting out of their laptop battery. Keep in mind that I will tell you what settings we found to be the most beneficial.
Power and sleep
Being new to Windows 8, my friend decided that we should start with the Power and sleep app, which you access from the Settings Charm by pressing [Windows]+[I] and selecting Change PC Settings | PC and devices | Power and sleep. When the Power and sleep app appears (Figure A), you can see that it's pretty sparse. (It would have been nice if Microsoft had spent the time to bring all of the Power Option settings to the new interface.)
The Power and sleep app only provides you with two functions.
The Power and sleep app only provides you with two functions and four controls. The Screen function allows you to determine when to turn off the screen, and the Sleep function allows you to determine when to put the system into sleep mode. It's a start, but pretty basic stuff if you already know about all the Power options that Windows has.
The power plans
In order really tweak your system's power settings, you will have to delve into the Control Panel and access the Power Options tool. When you do, you'll see the Power Options page (Figure B). By default, Windows comes with three power plans. However, since this Dell laptop comes with its own battery life extension features, there's an additional Dell power plan that has been factory-tuned for this laptop. Even so, you have to take that with a grain of salt, because the way that I use this laptop may not be the same as what was tested in the factory. For example, I may use the DVD drive more often or prefer to use USB powered external speakers.
The Power Options tool in the Control Panel provides you with access to several configurable power plans.
You'll notice that each power plan is accompanied by a brief description of the energy savings and performance of each plan. The Balanced and the Dell power plan, which is selected by default, are designed to offer full performance when you need it and save power during periods of inactivity. The Power saver power plan will save power by reducing system performance and is designed to help laptop users get the most from a single battery charge. On the other end of the spectrum is the High Performance power plan, which is designed to maximize system performance and responsiveness but will do almost nothing to save power. As such, from the standpoint of running a Windows 8.1 laptop on battery power, you might just want to ignore the High Performance power plan.
Adjusting plan settings
Adjacent to each of the power plans, you'll notice a link titled Change plan settings. Clicking this link takes you to the Edit Plan Settings page (Figure C). The Edit Plan Settings page provides the same basic settings that you found in the Power and sleep app. However, there's an additional setting that can help conserve battery power -- Adjust plan brightness.
The Edit Plan Settings page has one more configurable option than the Power and sleep app.
As you can see, there are two categories: On battery and Plugged In, under which you can alter settings. To conserve the amount of power used by the display on a laptop, you can adjust the amount of idle time that must elapse before the display is turned off. Of course, you can adjust the amount of idle time that must elapse before the computer is put into sleep mode. The drop-down menus for both the display and sleep options provide you with host of timing options (Figure D).
You can choose anywhere from 1 minute to Never.
You'll notice that the selected setting for turning off the display for the Dell power plan is 30 minutes. If you look at the Power saver power plan, you'll find that the selected setting for turning off the display plan is 2 minutes.
During our experimentation, my friend and I decided on 5 minutes as the amount of idle time that should elapse before the display is turned off. We figured that if you're away from the laptop for at least five minutes, then it will be good to turn off the display. You might think that having such a short period elapse before turning off the display would be annoying if you happen to be sitting at your laptop and reading or studying something on the screen, but it's really not. If you happen to be sitting at your laptop and reading, the screen will dim a few moments before it actually turns off. When it does dim, press any key and the display will revert to its original brightness setting. (It's best to use an inert key, such as [Shift], [Alt], or [Ctrl] when waking up the display so you don't inadvertently change or activate something.) Even when the screen does turn off, a simple key press brings it back to life rather quickly.
And while we're talking about brightness settings, you should note that you can also adjust the amount of power that's consumed by the display when it's in use by adjusting the brightness level setting. As you can see in Figure C above, the Adjust plan brightness for the Dell power plan is set at about 40%.
We found that we could drop the brightness level down to between 25% and 30% and still see everything on the screen just fine. Of course, the lighting in the environment where you are using your laptop will have an effect on what brightness level you choose.
You can see that the amount of idle time that must elapse before the computer is put into sleep mode under the Dell power plan is 10 minutes. If you look at the Balanced power plan, you'll see that the selected setting is 15 minutes.
We found that going with the 10 minute setting provided a nice equilibrium between power savings and ease of use. If your laptop is idle between 5 and 10 minutes, the screen turns off to save battery power, but you can get back to work with a quick press of a key. If you're away longer than 10 minutes, the computer goes to sleep to save even more battery power, but to get back to work, you must press a key and then sign in.
Adjusting the Advanced settings
If you want more granular control, you can click the Change Advanced Power Settings link, which you'll find on the bottom left of the Edit Plan Settings page. You'll then see the Power Options dialog box with a single tab titled Advanced settings (Figure E).
The Advanced settings dialog box provides you with access to very specific controls.
As you can see, in addition to the more common power settings, there are a host of power-consuming features and devices for which you can adjust settings, such as the hard drive, wireless adapters, and USB devices. I'll just cover a few of the more significant Advanced settings.
Hard Disk: Turn Off Hard Disk After
If you have a Solid State Drive (SSD), then you needn't worry about this setting. Even if you don't, the small spinning hard disks in a laptop really don't consume that much power. Regardless, you can squeeze a bit more power out of the laptop battery by turning off the hard disk. Keep in mind that this setting should be for a shorter time period than for putting the machine to sleep. Since we chose 10 minutes for putting the computer to sleep, we chose 8 minutes for turning off the hard disk.
Wireless Adapter Settings: Power Saving Mode
On the Wireless Adapter Settings: Power Saving Mode drop-down menu, you'll find four choices: Maximum Performance, Low Power Saving, Medium Power Saving, and Maximum Power Saving. Before you make a choice here, it's important to consider that the amount of power you'll save by adjusting this setting will vary depending on the wireless card in your laptop. Also keep in mind that performance will usually suffer with higher power savings. As such, I've found it to be safer to go with the Medium Power Saving setting.
Under the Sleep branch, you'll find Sleep after, Allow hybrid sleep, Hibernate after, and Allow wake timers. I already covered the Sleep after setting. Allow hybrid sleep really won't really help save battery power and, in fact, is set to off on all of the power plans. I recommend just leaving it off. By default, Hibernate after is set to 180 minutes on all but the High performance power plan. I recommend leaving it at the default. Allow wake timers will permit things like Windows Update to bring a system back to life. However, Allow wake timers are disabled on all of the power plans, so I don't recommend that you enable them on a laptop running on battery.
USB Settings: USB Selective Suspend Setting
By default, the USB Selective Suspend Setting is enabled. This setting allows the USB port drivers to shut off the power to USB devices that are idle. This will save power, because USB devices really don't need power the entire time they're connected to your laptop.
Processor Power Management
Under the Processor Power Management branch, you'll find Minimum processor state, Maximum processor state, and System cooling policy. The Minimum processor state setting allows you to choose a percentage of power to allot to the processor when it's inactive or performing minimal tasks. By default, the minimum setting is 5%, which will indeed save power. However, if and when processing power is required, the maximum setting of 100% ensures that the task at hand will have all of the available processing resources at its disposal.
The System cooling policy covers the amount of power the fan requires by altering the way that the processor functions. There are two states: Active and Passive. Active increases the fan speed before slowing the processor. Passive slows the processor before increasing the fan speed. You'll get the best performance by leaving the System cooling policy set to Active.
Evaluate with the PowerCfg utility
While you can always evaluate the effectiveness of your Power Options settings by using your system over time, Windows provides you with another way via the PowerCfg utility. When you run this tool, it will evaluate the efficiency of your Power Plan settings and provide you with a detailed report.
To use the PowerCfg utility, you'll need to open an Administrator Command Prompt, which you can do by right clicking on the Start button and selecting the Command Prompt (Admin) command. Then, type the command
After you press [Enter], the PowerCfg utility will begin analyzing your system's power-option settings. After a minute or so, you'll see a report brief (Figure F) and will be prompted to open the report titled energy_report.html for more details.
When the PowerCfg utility is finished analyzing your system's power-option settings, you'll be prompted to open the report file for more details.
You can type energy-report.html at the prompt to launch Internet Explorer and open the HTML report file.
When the report opens (Figure G), you'll see a header with basic system information followed by color-coded sections that indicate the severity of the problems that were detected. Pink indicates errors, yellow indicates warnings, and white indicates general information. You can use this report to make adjustments to your power plan settings.
The report is divided into three color-coded sections that provide details on the efficiency of your system's energy usage.
To delve even deeper into the power-management information contained in the report, you should download the "Using PowerCfg to Evaluate System Energy Efficiency" document from the Windows Hardware Developer Center. This document provides you with additional information on how to use the PowerCfg command as well as detailed explanations of how to understand and solve the reported energy-efficiency problems and warnings.
What's your take?
Are you using Windows 8.1 on a laptop? Have you tweaked the Power Options settings to get more out of a single battery charge? Will you use the PowerCfg command-line tool to evaluate the efficiency of your Power Plan settings? Share your opinion in the discussion thread below.