Going Green: Get Lower PC Energy Costs Fast

Those issues aside, the latest trend appears to be what is called the carbon footprint. The carbon footprint relates to the amount of greenhouse gases that a product or person releases whether by their use or actions. While many of us don't have control over how a product is made (other than refusing to buy it), we can control our energy use, which indirectly affects the carbon footprint.

Many component manufacturers are taking notice of this trend and are making products that perform as well or, in some cases, better than older models, while drawing less power. By using these components to build a new PC, or substituting just a few in an aging one, a considerable reduction in energy use can be achieved.

At the forefront of this trend is Intel, with its Atom processor. Originally designed for small, battery-operated, single-use devices that would benefit from an always-on Internet connection, the Atom processor soon became the building block for a new classification of computer called the netbook. Soon that popularity moved to the desktop and relatively inexpensive Atom-based PCs are now starting to reach the market.

At the same time, Atom-based motherboards (with the CPU already mounted) became available for system builders and do-it-yourselfers. For those who don't need a PC to do much more than access the Internet, check e-mail, and maybe do some word processing, building a system around the Atom could save energy-related expenses, as well as up-front costs. When the CRN Test Center used Intel's D945GCLF2 motherboard (with the Atom 330 processor) to construct a PC that approximates the functionality of a netbook, we ended up with a computer that is capable of performing day-to-day tasks while only drawing 46 watts under load. By comparison, our standard desktop testbed draws almost double that amount at idle and more than triple under the same exact load.

While the Atom can't simply be swapped into an existing PC, most components can be. During our tests, the part that had one of the most significant effects on power consumption was the graphics card. Typically, graphics integrated into the motherboard will have a lower power draw than a separate card. While these on-board chipsets historically performed at or below par, some of the newer motherboards can now support even built-in, high-definition video.

If you prefer to use a stand-alone graphics card, or are looking to replace one in an older system, many of the current offerings can help reduce energy usage too. When it comes to controlling the power draw of your video card, the first rule-of-thumb is to determine what the system will be used for, and installing a card with the correct specs for the job. This is one of the areas where extra speed and memory can hurt. Aside from the higher electrical drain faster graphics processors have, they also generate much more heat. This in turn requires more energy for whatever cooling system is in place. For a computer that isn't going to be playing the latest in video games, a high-end graphics card is overkill. Using a less powerful GPU will also lower the cost.

If usage requires a quick video card, there are still some energy-saving options. Many new cards are designed to run relatively cooler than previous models and some use hybrid cooling, which will regulate when its fan is used and at a certain speed. Besides increasing power efficiency, this also makes for a quieter system.

Gamers aren't out of luck either. Cards like the just-released ASUS Matrix ENGTX260 are designed for overclocking and, as such, have adjustable voltage regulators. While this feature is primarily used to increase the voltage while boosting the speed of the GPU, it can just as easily lower the voltage when the system is being used for less graphic-intensive jobs.

According to a 2008 IDC report, power efficiencies, controllers, fans, etc., equate to approximately 1 watt lost for each HDD watt. In addition, it takes 1 watt to cool 1 watt. That means that a typical hard drive, specified to draw 12 watts, is actually responsible for consuming 48 watts at the outlet -- four times the drive's usage. By means of various technologies, hard drive manufacturers have been hard at work lowering the power draw of their products.

One such drive is Hitachi Global Storage Technologies' Deskstar P7K500. Hitachi has implemented a set of power-saving technologies to reduce the P7K500's active and idle power consumption by up to 40 percent over the previous generation. With idle power utilization of 4.8 watts (3.6 watts on the 250-GB capacity model) and active power requirements of 8.2 watts (6.4 watts for the one-disk model), the P7K500 utilizes just over half of the idle power typically allotted to hard drives in Energy Star-rated PCs.

Western Digital's contribution is the GreenPower Technology line, including the Caviar Green models for desktop use. These drives include multiple features from improved spin-and-seek speeds, transfer rates, and caching optimization to platter stability and vibration reduction, which result in an average power savings of 4 to 5 watts per drive.

Although it is doubtful that anyone would take a faster, quad-core CPU out of an existing PC to replace it with a less expensive dual-core processor, new system builders can save both money and electricity by using these older models. Similar to the graphics card, taking the computer's planned function into consideration can help avoid overkill. If the end user is not going to be doing any tasks requiring a quad-core CPU, a processor such as any in Intel's Core 2 Duo line may be satisfactory.

Specifically designed for energy-efficiency, the Core 2 Duo has two cores built on 45nm technology, up to 6 MB of shared L2 cache and up to 1333 MHz Front Side Bus. Although obviously not as powerful as the newer quads, we find them to be extremely versatile. And if you put some of the cost savings into adding more memory, the loss in performance would appear negligible to the typical user.

Clearly no conversation on a computer's energy consumption would be complete without mentioning the power supply. Simply by means of its function, you cannot really lower a PSU's consumption without lowering the amount of power it supplies. To that end, most modern-day PSUs incorporate features to make them as energy-efficient as possible, thereby allowing you to consider using a lower wattage unit.

80 PLUS is an electric utility-funded incentive program created to integrate more energy-efficient power supplies into computers. An 80 PLUS-certified PSU must be 80 percent or greater energy-efficient at 20 percent, 50 percent and 100 percent of rated load with a true power factor of 0.9 or greater. This makes an 80 PLUS-certified power supply substantially more efficient than typical power supplies.

Systems used for basic tasks would do well with Antec's EarthWatts line of PSUs. Available in models up to 750 watts, Antec bills EarthWatts as "one of the most environmentally friendly power supplies available." All 80 PLUS-certified, EarthWatts power supplies also feature Active PFC (Power Factor Correction), which alters the input current, thereby reducing electrical costs.

For users whose requirements go above the highest 750 EarthWatts model, Antec's TruePower Quattro power supplies offer 850- and 1000- watt units that incorporate many of the same energy-efficient features as EarthWatts PSUs.

Whether building a new system, or fine-tuning an existing one, with careful component selection and a little tweaking, significant energy savings can be realized.