Labs

Ultimate PCs

At the end of each review, there are five star ratings: one for Performance, another for Quietness, a third for Features & Design, then Value for Money and a final Overall rating. We don't just pluck these figures out of the air: they're calculated using a complex array of benchmark results, objective scores and subjective quality ratings.

Performance

We put each machine through its paces in a rigorous series of tests using real-world applications such as Word, Access and Photoshop.

The overall 2D result is relative to a score of 1.00 from our reference PC - a dual-core 3.2GHz Pentium D 840 system with 1GB of PC3200 RAM, a 10,000rpm Western Digital Raptor hard disk and an Nvidia GeForce 6600 GT graphics card. If a machine scores 1.50, it's 50% faster than our reference machine overall.

Since these are ultimate PCs, our standard 3D tests won't cut it. Instead, we created a custom Call of Duty 2 test: all the monitors have a resolution of at least 1,680 x 1,050 so we opted for that, and other settings included 16x anti-aliasing and 16x anisotropic filtering, with the usual intensive Extra textures.

To test the DirectX 10 capabilities of the graphics cards, we also use the Call of Juarez benchmark utility, which features advanced effects such as next-generation material shaders. We run it at three levels, beginning at 1,024 x 768 with Low settings; then 1,280 x 1,024 with Balanced settings; and finally, 1,680 x 1,050 with High settings - a test we've found to tax all but the latest SLi systems.

Quietness

Unlike any other UK magazine, we send every PC in the Labs to Intertek Research & Testing Centre to find out how noisy they are. Testing is carried out in an acoustically treated listening room, using a precision sound-level meter with an "A-weighted" audio filter. The results are in dBA: levels of 25dBA can be compared to the background noise of a bedroom at night, while 45dBA represents a typical living-room's background noise. Results are based on four readings: front and side while idle, and the same again under intensive use. Intertek also measures the power consumption of each PC.

Features & Design

The Features & Design score takes objective measurements, including the hard disk capacities and setup, the capabilities of the optical drive and the inclusion of wireless, TV tuners and other extras. Warranties are examined and each company's performance in the Reliability & Service Awards is taken into account.

More subjective ratings are given to extras such as speaker sets and monitors, which can't be scored objectively. In these cases, a panel of judges rates them on a variety of criteria - such as style, build, sound/image quality - and the results are averaged out.

Value for Money

The Value for Money score is based on a weighted average of the Performance, Quietness and Features & Design scores; we then factor in exactly how much each machine costs (including delivery) for a bang-per-buck result.

Overall

The Overall rating is a straight average of the Performance, Quietness, Features & Design and Value for Money scores. Occasionally, it may appear higher or lower than expected due to rounding.