Buying the right PC

How much power? How much money?

You know that some computers cost less than �400, others more than three times that. The received wisdom is that you should buy the most powerful computer you can afford. But you don't need a Ferrari for the weekly supermarket run. So how much is enough, and what should you look out for?

The processor is the basic engine of a computer. The speed of the processor is determined by what's called its clock rate, measured in megahertz (MHz) or more usually these days, gigahertz (GHz). Naturally, the higher the MHz rating the better - but the fastest processors will be more expensive.

The processor is one of the elements that will determine how fast the computer is, but it's not the only one. Overall performance is determined more by a combination of hardware components working with the software setup.

It is worth noting that the two main processor manufacturers - Intel and AMD - have different models for different price and capability points. Intel's budget processors are called Celerons, AMD's carry the Duron label. The high-performance models are Intel's Pentium series, and AMD's Athlons. If you're into heavy-duty arcade games or digital video editing, you'll need a Pentium or Athlon. For just about anything else they aren't essential, so you might as well save your money.

Bottleneck

The way Windows works, the real bottleneck for most PCs is memory (RAM). The more memory a computer has, the greater the number of applications and operations it can run without slowing down - or giving up altogether. So in general, the more memory the better. 256MB is the absolute minimum these days; 512MB or more is your target. If you're on a budget, go for 256MB now - it's easy (and getting cheaper) to add more memory later.

�In practice that's almost impossible to anticipate with real accuracy.�

The third key components is the hard disk (or 'hard drive'). Since this is where all files and programs are stored, you should ensure that the disk will have enough capacity. In practice that's almost impossible to anticipate with real accuracy; once you start using the computer, you'll find that files proliferate as new programs are added.

Disk capacities are measured in gigabytes (GB) and you should probably reject anything less than 20GB. Most new PCs come with 80GB of hard disk space, which should be enough for most uses - but you'll see models with many times this capacity. Even then, you might still run out of space if you start digitising large amounts of music or video.

Practical

The cheapest display is a 14in CRT (TV-type) screen, but they're really too small for practical use by today's standards. A 15in or 17in CRT is your baseline - the measurement is across the diagonal of the screen.

Much better is a flat screen; they're considerably lighter, take up less room and don't start humming three months before they fail. Many PCs now come with a 15in LCD screen; a 17in screen is better, but they are pricier and start having a serious impact on the total price of your system.

You'll need a variety of sockets to plug things into the PC. Most modern devices use a USB connector, a small flat plug; you may need to cope with a printer, modem, scanner and digital camera all at the same time, so look for four USB sockets as the minimum.

Congestion

If you expect to use different devices at different times, look for a base unit with USB sockets on the front - otherwise you'll spend a lot of time on your hands and knees, poking around the cables at the back.

�You may never use these, but you may as well have them as not.�

Most PCs will also have a selection of older-style sockets, which can reduce the congestion on USB ports - probably a specialised parallel-port socket for a printer, one or two COM ports for modems, maybe a game port for joysticks and game controllers. You may never use these, but you may as well have them as not.

There will also be a couple of small identical-looking round sockets for mouse and keyboard, plus tiny jacks for speakers to plug in. Thankfully, these are often colour-coded to simplify the process of wiring everything together.

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What's in a name?

PCs are pretty well standardised - a rectangular box with a main circuit board inside, a rack arrangement for slotting in components like hard disks and CD-ROM drives, slots for memory and smaller circuit boards, and so on.

The name on the front of the PC refers to the company that assembled the parts into a system. That company almost certainly did not manufacture the parts; they bought them from individual suppliers - just as a car maker buys in components from individual suppliers. Because the designs are standardised, and because all the component suppliers follow those designs to maximise the size of their market, all computers do tend to look much the same.

�Since the PC maker's reputation is at stake, it makes sense for them to buy the right components.�

But since the PC maker's reputation is at stake (not to mention their legal liability), it makes sense for them to buy the right components - the ones that work well together, that offer maximum reliability, that leave the customer satisfied and able to recommend the brand. For your own peace of mind, it might be worth paying extra for a bigger name.

The only exception to bear in mind is Apple's Macintosh range. The divide between Macs and Windows-based PCs is narrowing, with the rise of common technologies like USB and other changes inside the boxes. And few would argue that Macs aren't generally prettier and cooler than PCs. But from a practical perspective, for most businesses, it's no contest. Windows-based PCs are cheaper for equivalent capability, there's a lot more software available for them, they are more expandable - and everyone else uses them.

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