Buying a green PC not as easy as you may think

Washington, Sep 2 : It's not easy being green - especially when it comes to computers.

While for years the computer industry has been touting green components and working to reduce the power used by individual components, a typical PC with monitor still uses about as much electricity as three or four 100 watt light bulbs.

Consider that many personal computers are left on all the time, and you're looking at some serious power consumption - and some hefty electricity bills.

What you can do to reduce the power consumption of your current computer may be limited.

But when it's time to look for a new machine, it'll pay to keep an eye on how much power the machine will use. That's because there's never been a greater disparity between the power used by energy-sipping models and that used by the most powerful PCs. Here's how you can distinguish the green PCs from rest.

The size of a computer case doesn't have to mean anything about how power-efficient a computer is, but it's often a clue. Larger cases are typically used when heat dissipation is an issue, and heat dissipation is a concern when power-hungry components are at work.

Smaller cases are often used to house lower-power or energy-efficient components. So while smaller doesn't always mean better, it's a safe bet to assume that it is.

Notebooks - the smallest of all personal computers - are typically the most power efficient as well. They're designed from the ground up to be able to perform standard computing tasks while drawing a minimum of power, and they go into power-saving mode more quickly than a standard desktop, since at times they have to run on a battery. So notebook users today can almost always boast of having the greenest computers.

You might think that the latest crop of powerful processors are also the most power-hungry. But you'd be wrong.

Advanced manufacturing techniques have not only allowed the big chip makers to cram two or even four processing cores on a chip that used to house only one, but the latest dual-core processors use about half as much energy as earlier models. Quad-core processors aren't quite so energy efficient, but they're still better than the older generation of chips.

So if you're looking for a green desktop, look for midrange chips from the latest lines from Intel and AMD.

Intel's new Core 2 Duo vPro line improves upon the already stellar power-saving features of the original Core 2 Duo line, and AMD's Phenom processor with its "cool and quiet" technology puts energy-savings in the forefront.

Today's most powerful graphics cards are also the hottest - literally - and the most power hungry. Graphics that are integrated onto the motherboard, by contrast, are the most energy-efficient. But they're also often just marginally acceptable.

So your best bet if you're buying green is to look for a midrange dedicated graphics card - whether in your desktop or notebook - and to eschew the expensive models that are designed primarily to run the latest games. Those high-end graphics cards will not only hit your wallet up front, but they'll keep depleting your budget by using more energy than any other single component in your computer, including the processor.

Power supplies - the piece of a computer that supplies power to the rest of the parts in a computer system - are not a component that computer buyers generally pay much attention to. But for those buying green, that needs to change.

It's true that the amount of energy that a power supply draws depends greatly upon what exactly is installed in the computer. But power supplies themselves have often been energy-wasters in the past.

If an earlier generation power supply had to provide 300 watts of power to the components in a PC, for example, it might actually use 500 watts in order to produce that power.

The industry's answer has been the relatively new 80 Plus certification program, which requires power supplies that wish to wear the 80 Plus logo to be "at least" 80 per cent efficient.

In other words, a power supply that needed to provide 300 watts of power to the components in a computer could draw a maximum of 375 watts in order to gain the 80 Plus seal of approval. So when you're buying a green PC, look for computers that boast an 80 Plus logo.

When LCD displays started to gain traction in the market, they were not only hailed as space savers on the desktop but also as power savers, as well. That was when the average size of an LCD was 14, 15, or 17 inches.

Today, popular LCD sizes are 21, 24, 26, and even 30 inches diagonally - the size of an average living room television set from last decade. And with the increase in size has come a proportional increase in power consumption.

Being able to identify and purchase green computer products over less energy efficient ones is smart, but even smarter is changing your behaviour to maximise energy conservation. Use the energy-saving features of any computer equipment you own.

Turn off monitors, printers, and other devices that aren't being used. Shut down your computer entirely overnight or when not in use for a long period of time. The greenest computers of all are those that are not turned on.

Setting aside a specific time of the day to handle chores that require the computer and turning off that machine at all other times is far preferable from an environmental standpoint than leaving the machine on all day and using it every now and then.