- The average laptop consumes five times less energy than a desktop PC. So, if you're going to own only one computer, seriously consider a laptop instead of desktop model. If a laptop won't work for you, think about whether you really need the biggest desktop you can afford or whether you might be able to get by with what's known as a "small form-factor" PC. These smaller machines are designed to take up less space on your desktop, but they have the advantage of drawing less power, too.

- Although each generation of microprocessors is speedier than the previous one, smart engineering means that they often also use less energy at the same time. For example, Intel's Core 2 Duo desktop processor is up to 40 percent faster and more than 40 percent more energy-efficient than its single-core predecessor.

-More than 80 percent of the lifetime energy consumption of a PC occurs before you buy it.

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