2. Add more memory
Regardless of whether you use a PC or Mac, when it comes to performance, more RAM equals better performance and lower total power use. RAM chips use so little power that adding 4GB or 8GB has a marginal impact on its total power use -- more RAM can, however, save power by reducing the system's use of virtual memory.
How? Virtual memory is actually hard drive space that is used to store items from memory when the system runs out of unused physical memory. Because the hard drive uses a lot more power than RAM chips, using virtual memory eats into efficiency and battery time. So adding RAM can not only make your system more efficient, but save battery power as well.
3. Make storage more efficient
Compared to a conventional hard drive, an SSD not only speeds things up but also uses less power -- so you might want to consider upgrading your storage. However, if you can't afford a new drive (or just don't want to bother), a traditional hard drive's hunger for electrons can be tamed by adjusting its power management settings.
For Macs, you can control when the drive goes to sleep in the System Preferences Energy Saver pane. In the Battery tab, start by checking the box that says Put the hard disk(s) to sleep when possible. Apple sets 10 minutes as the default period of inactivity before the drive nods off, but you can tap into the system's pmset utility to adjust it. Here's what you do:
Go to Terminal (which you'll find in the Utilities folder, or you can just search for Terminal). Type sudo pmset disksleep X, where X is the length of time in minutes that you want the system to wait before putting the drive to sleep. (Warning: You'll need the administrator's password to do this.)
The pmset utility lets you set when your Mac's hard drive goes to sleep.
With a Windows system, you can use the Change Advanced Power Settings page in the Power Options portion of the Control Panel.
I generally set my system's hard drive to turn off after 10 or 15 minutes of inactivity. It'll take a second or two for the device to spool up when you need it, but the extra minutes of battery life make it worth the wait.
4. Lessen your display time
Fewer pixels put less of a power load on the graphics chip, video memory and display panel. So although I'm wowed by the latest high-resolution notebook screens, I don't really do much more than view the occasional YouTube video. As a result, when I shop for a notebook, I get the lowest resolution screen that is acceptable for my purposes. These days, that's generally a 1280 x 800 display.
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