I am looking for an energy-efficient notebook PC. My current machine gets very hot -- presumably guzzles energy like nobody's business -- and is also very heavy to carry around. Wiebina Heesterman
Most portable PCs are about as energy-efficient as the manufacturers can make them, because power conservation provides longer battery life. Inevitably, some waste heat is generated by the operations of the processor and the hard drive. You can minimise this by choosing a low voltage or ULV (ultra-low voltage) chip. Recent examples include the Intel Core 2 Duo U7500 and U7600 ULV processors with a "thermal design power" of only 10 Watts. Unfortunately, ULV chips tend to be relatively slow (the U7600 is a 1.2GHz processor) and expensive, and are mainly used in ultra-mobile designs.
A cheaper alternative is the 1.5GHz Via C7-M processor which is billed as having "12W peak power". It was used last year in the Everex NC1500 Energy Efficient Notebook PC, but I don't know how well it performs.
However, the biggest gain would come from have a more efficient mains converter, since these tend to generate a lot of waste heat.
In the future, solid state disks (SSDs) -- drives based on Flash memory chips instead of rotating platters -- should also offer an energy-efficient alternative to hard disks. At the moment, these are still too expensive for the mainstream market.
Since 1992, the US Environmental Protection Agency and the US Department of Energy have been leading the way with their Energy Star programme. Their new Version 4 specification comes into effect on July 20 (http://www.energystar.gov/index.cfm?c=revisions.computer_spec). This is aggressive, and I'd regard any notebook PC that meets most of the Tier 1 requirements as acceptable. Leading manufacturers such as HP, Dell and Toshiba target these specifications for the systems they sell to US government agencies.
Note: This is the full answer. The printed version was somewhat reduced.....
