How to buy a new PC: Choosing the right one

Today's modern desktop PCs offer a wealth of options: You can go for a PC with a fixed retail configuration, or you can customise your system by stepping through a sometimes dizzying array of choices from a configure-to-order vendor. The resulting array of components is no longer wrapped up in a beige box, but in a colorful shell of highly variable shape and size, differentiated by indecipherable naming conventions.

Presented with so many possibilities, you need to narrow the field by considering what you want to use your new desktop for. Are you an avid photographer looking for a speedy but cost effective platform for editing high-resolution photos? If so, you'll benefit from buying a machine with extra RAM and a discrete graphics card. If you've acquired an extensive media collection, and want an inexpensive and compact way to pipe it to your HDTV, a compact PC tailored toward media sharing and playback may be your best bet.

Whatever your needs, you can find a desktop configuration to fit the bill.

Desktops fall into three major categories, each with its own range of price and performance: compact PCs, all-in-one PCs, and classic tower PCs (which we subdivide into budget, mainstream, and performance categories). Each style of machine has different strengths and weaknesses, and choosing the one that's best for you depends largely on how you plan to use it.

Once you've picked the appropriate desktop category, our guide to PC specifications will help you pick a machine that delivers the performance you need, while staying within your budget.

Compact PCs

As the smallest members of the desktop computer family, compact PCs often omit features to deliver computing power in a space saving package. The combination of energy efficient components, quiet operation, and small size makes compact PCs ideal for people who want a nonintrusive machine. A typical compact PC costs between £200 and £400, though the price goes up as you add upgrade options.

Compact PCs tend to be equipped with notebook or netbook components, such as Intel Atom processors. This limits their usefulness in tasks that demand lots of processing power, but it makes for quiet, energy efficient operation. Not all compact PCs are created equal, however, so pay attention to specifications when shopping. Some compact PCs are configured for as low a bottom-line price as possible; others are packed to the gills to deliver optimal performance in a compact system.

Most compact PCs rely on integrated graphics. In some cases (depending on the CPU and the integrated graphics chipset), anything more complicated than a Flash-based browser game will be unplayable, but you will be able to eke out competent media streaming with Intel integrated graphics. A machine toting nVidia's Ion platform, like the Acer Aspire Revo R3610, usually fares much better. Gaming still isn't an option, but 1080p video is, whether you stream from a larger PC or over the web.

When assessing smaller PCs, keep an eye on the ports. The smaller the footprint, the fewer features you can reasonably expect, and that includes fewer connectivity options. Though you'll get a VGA port and (on average) six USB 2.0 ports, many compact PCs also offer HDMI, an asset for home theatre setups. The typical hard drive size is 320GB, though 250GB is also common and we've seen compact system carrying up to 1TB (for a £70 upgrade premium).