Features

Complete guide to green computing

20070110 [PC Pro]

Buy a green PC

1 Fujitsu-Siemens Esprimo E5615

Fully configurable, greener than most and reasonably good value for money

We looked at a more powerful specification of the Esprimo E5615 last month (see issue 148, p93), but the family can be configured with all manner of AMD processors on the AM2 platform. This model has an Athlon 64 3500+, but it can also support energy-efficient Sempron and Athlon X2 CPUs: they have a TDP (thermal design power) of 35W and 65W respectively, rather than the standard 62W and 89W of their full-power siblings, so obviously require less cooling. This fits Fujitsu-Siemens' approach to reduce TCO by lowering the energy-consumption, and it continues with the inclusion of a switched monitor outlet. This means the display is powered directly through the system, so when the PC is switched off it also cuts the power to the TFT. Fujitsu Siemens has long been committed to environmentally conscious design, being one of the first companies to offer lead-free soldering. It also uses N2 gas rather than water to wash the circuit boards after soldering, saving valuable resources. The company even sends out systems in recycling-friendly boxes. The E5615's BIOS-controlled fans are, start-up aside, kept to an inaudible hum. But next to the Tranquil T7 it's still relatively noisy and power-hungry, consuming 50W when idle. This is to be expected, as it's much more of a standard office PC than its little rival. It scored a perfectly respectable 0.89 in our intensive benchmarks, and it has upgradability in its favour thanks to the conveniently accessible, if somewhat unattractive, chassis.

2 Tranquil PC T7

Amazingly low power consumption and an innovative silent chassis, but performance suffers

Tranquil PC's tiny new T7 takes a wholly different approach to the green issue, with an interestingly designed fanless chassis made up of heatsinks on five of the six sides. The only moving part is the 2.5in hard disk, so to all but the most sensitive ear it runs silently. It's all based around the company's TranCool technology, which aims to disperse heat efficiently away from both the CPU and north bridge. As well as silent running, this means there's no dust sucked into the system, increasing its longevity, and it also means Tranquil must use ultra-low-power components in its construction. The T7 is built upon VIA's new C7 platform and, despite running at 1.5GHz, the processor consumes just 12W at full load. The frequency is stepped down when idle, so the entire system consumes an amazing 15W, rising to just 21W when benchmarking intensively - genuinely staggering when top-end PCs chomp through almost 300W at full pelt. As Tranquil is a sponsor of the Zero Carbon Footprint movement, it will even plant trees to offset some of its emissions. As you'd expect, it's not a PC for everyone. It trundled through our office test with a score of 0.42 (so it's only 42% as fast as the reference 3.2GHz Pentium D PC) but it isn't aimed so much at a general office environment. Instead, it can be fitted in vehicles, and is already being embedded in hospitals and many other public locations. Other configurations are available, with both lower-power and faster CPUs supported, and flash-based storage is an option if absolute silence is required. A version with an integrated optical drive will be available in March, although it will stretch the dimensions a little. But for now, the diminutive size and noiseless running more than justify the price, and there's sure to be a market for such an innovative system.