The computer helper: Know your power options (Feature)

By Jay Dougherty Aug 28, 2010, 3:06 GMT

Washington - Computers need power - and plenty of it. But if you're like many, you have reasons to be concerned about how much power your computer actually uses. You might want to lower your electricity bill or simply reduce the impact that your computing has on the environment. Or, if you frequently find yourself on the road, you no doubt want to reduce the amount of power that your notebook uses so that you can get longer life out of a single battery charge.

When it comes to energy use, the good news is that you have plenty of options available to reduce the power consumption of your PC. The bad news is that it's sometimes difficult to know which power saving options to use in which situation. Read on to find out.

Q: What's the difference between sleep mode and hibernate mode on Windows?

A: These are two power-saving options. Both are designed to allow you to resume work on your PC faster than if you shut your computer down entirely.

You can remember the difference between sleep and hibernate by remembering the difference between the words 'sleep' and 'hibernate' before computers came along. Essentially, when you sleep, you can wake up again pretty quickly. If you were to hibernate, you'd be unavailable for a bit longer.

The same goes for your Windows computer. Sleep mode shuts down some components of your PC, but everything that is active in memory (RAM) remains alive, so that when you 'wake' your computer up by pressing a key or the power button, the machine returns to the state in which you left it almost immediately - with applications, browser windows, and documents in exactly the same state.

As you might imagine, a computer in sleep mode continues to use some power, since the contents of RAM must be maintained. So if you're using a notebook computer on battery, be careful: putting your notebook to sleep can still result in a dead battery after a while. Use this mode when you know you'll be returning to work on your computer shortly.

Hibernate mode, by contrast, takes a snapshot of everything you have in RAM and writes it to a special hard disk file. Hibenate mode then turns your computer off entirely, using no more electricity than if you shut the PC down the conventional way. The advantage of hibernate mode is that your PC will boot up a bit faster than if you booted it after a complete shutdown. Use this mode when you plan not to need your computer for a while.

Q: I'm ready to buy a desktop computer. What can I do to make sure it doesn't use much electricity?

A: Some manufacturers these days provide data on how much power their machines use. Compare these ratings to determine which model might be most power-efficient.

Beyond power ratings, though, there are some general guidelines you can use to ensure that your PC sips power rather than gulps it. First, avoid machines marketed for gamers. These units typically have power-hungry components - with graphics cards that in some cases consume as much power as entire power-efficient PCs. These machines, in short, are designed with performance in mind, and they achieve it often at the expense of energy conservation.

Instead, look for computers geared toward everyday use, with integrated (fanless) graphics cards and perhaps, if you can afford the upgrade, with a solid state disk (SSD) rather than a conventional hard drive. Pay attention, too, to the wattage of the unit's power supply. If you see power supplies of 500 watts or higher, you know you're not necessarily looking at a power-efficient machine.

Finally, if power efficiency is a primary concern, you may wish to reconsider your choice of a desktop computer altogether. Notebooks are typically far more power-efficient. And if you look for a business-class model with an optional docking station, you can have most of the conveniences of a desktop - including the ability to attach a monitor, keyboard, mouse, and many other peripherals - with the portability and energy efficiency of a notebook.

Q: I'm preparing for a long flight. What are some tips for maximising battery life while I'm away?

A: User your operating system's Power Saver mode, which will automatically dim your screen, put your CPU into a lower-power state, and also put your notebook to sleep faster than would otherwise be the case.

Also, unplug any USB devices that you don't need. These require power, even when not in use. Along the same lines, if your notebook is equipped with bluetooth or wifi that is not in use, disable those features. You will probably need to reboot your machine to do so, as disabling these features is usually done by accessing the computer's BIOS setup screen, which controls whether the hardware in your computer is active or inactive. Pressing F2 or the Del key upon bootup will typically get you into the BIOS. --- Have a computer question? Send it to jaydougherty.dpa@gmail.com.