Labs

Business PCs

At the end of each review, there are five star ratings: one for Performance, another for Quietness & Power, 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, however: 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, employing the same tests for PCs and notebooks.

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 in our tests, it's 50% faster than our reference machine overall.

Quietness & Power

Unlike any other UK magazine, we send every PC in the Labs to Intertek Research & Testing Centre to find out how noisy it is.

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 and, to put a rough perspective on measurements, levels of 25dBA can be compared to the background noise of a bedroom at night, while 45dBA represents background noise in a typical living room.

Results are based on four readings: front and side while idle, and the same again but under intensive use. Intertek also measures the power consumption of each PC, while idle, in sleep/standby, and off.

Features & Design

The Features and Design score takes into account an array of objective measurements, such as the hard disk capacities and setup, the capabilities of the optical drive and the inclusion of wireless adapters and other extras. Business PCs are also scored on their range of security features, such as TPM chips and lockable cases. Warranties are examined and each company's performance in the Reliability & Service Awards 2007 (www.pcpro.co.uk/awards2007) is taken into account.

More subjective ratings are given to an array of areas, such as the layout on the inside of each case and the overall innovation and design of each PC, which can't really be scored objectively. In these cases, a panel of judges rate them on a variety of criteria - such as style, size, build quality, expansion potential - and the results are averaged.

Value for Money

The Value for Money score is based on a weighted average of the Performance, Quietness & Power and Features & Design scores, with the latter two weighted higher to reflect the fact that cutting-edge performance isn't a vital factor in a business PC. We then factor in how much each machine costs (including delivery) for a bang-per-buck result.

Overall

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