Processor speed

Choosing the central processor unit (CPU) chip is one of the most important choices in buying your PC. If it’s been a few years since you’ve bought a PC, you might be familiar with choosing CPUs based on their GHz rating. That’s no longer the sole thing you should be concerned about – the type of processor makes a big difference (Intel’s Core 2 Duos are considerably faster than Pentium 4s at the same GHz, for example).

In the last couple of years, processors have also taken an interesting turn: rather than simply bumping up the speed, CPU makers are now packing multiple processing cores into a single chip. Your computer splits up tasks and works on them in parallel, boosting the effective speed of processing. The catch? Most software hasn’t yet been very effectively optimized for multi-core processing, so it doesn’t get much benefit from more than two cores (“dual core”). Quad-core processors are mainly useful for heavily mathematical tasks like video encoding and non-gaming 3D rendering.

It’s worth going for a dual-core CPU such as an Intel Core 2 Duo  - for a start, they are barely more expensive than single core chips, and they also help with the general smoothness of your computer. If one program is hogging a CPU core, Windows can still run reasonably smoothly on the other core, rather than the whole system slowing down.

You’ll also need to choose between an Intel or an AMD CPU. The two manufacturers are always at each other’s throat trying to outdo each other on speed, so it’s impossible to say which is faster. The best thing to do is to read CPU reviews in computer magazines and websites at the time you’re thinking of buying your PC.

Motherboard

You’ll only need to choose the motherboard if you’re specifying every component of the PC and getting a shop to build it, or building it yourself. Brand-name PCs use their own motherboards and pre-priced PCs at shops will be based around a certain motherboard too.

The motherboard you buy must be matched to the CPU you buy. There are several different CPU socket types, and boards for Intel CPUs and AMD CPUs are totally different.

Motherboards are mostly differentiated by the extras that are included on them over and above the basic reference design provided by the original motherboard designer such as Intel or NVIDIA. These extras may include RAID (for automatic hard drive backup to a second drive, or for higher performance throughput by ‘striping’ data across multiple drives), built-in support for wireless networking, Firewire support for connection of video cameras, and so on.

Some boards are designed with overclockers in mind – people who want to be able to tweak the settings on their board to drive chip speed above the original speeds set out by the manufacturer. This can be worthwhile – most CPUs have a lot of headroom in them to allow them to run faster than the manufacturer’s spec, but it does mean you’ll need to learn about the intricacies of overclocking as well as investing in specialized cooling systems to keep the PC’s heat under control.

In simple terms, if you want a motherboard, buy from a well established brand-name such as Intel and you’ll benefit from better ongoing support and automatic software updates and so on.

RAM (Memory)

RAM – the memory space your computer uses to hold active programs and ‘think’ while it’s switched on – has always been an expensive component of the computer, but offers big speed increases if you add more.

As a guide, Windows XP will run reasonably well in 512MB of RAM, but bumping that up to 1GB will provide good performance. RAM is now so cheap that if you’re not under a tight budget, you may as well go up to 2GB as it will provide lots of headroom for big applications like Photoshop, or running one operating system (such as Linux) inside another (like Windows) using virtualization software.

Vista is considerably more RAM hungry. For ‘OK’ performance, 1GB is the minimum, and 2GB will provide good speeds. Put as much memory in your PC as you can afford – however, the maximum the mainstream version of Vista can use is about 3GB. To go beyond that, you’ll need to step up to the 64bit version of Vista, which may have problems with compatibility with software that wasn’t written specifically for it.

You need to buy RAM that is the appropriate type and speed for your motherboard. If you are specifying the components for your PC individually, be sure to check what the right type of RAM is before buying or specifying it.

Storage: too much is never enough

One thing that PC users can never have enough of in the era of downloadable TV shows, movies and music is storage space. The good news is that enormous hard drives are very affordable indeed.

For most users, a 250GB drive will be a good starting point, providing storage space that will last for a fair while. As a guide, a TV episode takes about 0.5GB and a downloaded movie takes about 1GB – 1.5GB. A backup of a DVD can take up to 9GB, and video downloaded from your video camera for editing takes about 12GB per hour of video.

If you want to splurge, 500GB drives are also very affordable. It’s only at the 750GB and 1TB points that hard drives start to get expensive. Of course, most desktop PCs come with multiple drive bays, so you can always buy multiples of the cheaper hard drives (such as 3 x 500GB) to get a large amount of storage.

If you have a digital camera, you may want to look into getting a PC with a card reader built in to the case. They provide faster downloads than by connecting your camera to the PC, because the card is being read directly by the computer. Card readers are common in brand-name PCs, but if you’re buying from a local PC supplier, you’ll need to specifically mention that you want this – they’ll install a card slot into the one of the drive bays on the front of the case. Usually these card readers provide multiple slots for different types of cards – but make sure the particular type of card your camera uses will have an appropriate slot in the card reader that is going to be installed into your PC.

Choose your graphics card carefully

There are three main choices in video cards: motherboard built-in graphics (fine for everyday tasks but not usually enough for gaming), a mid-range graphics card that will cost around $250 - $300 (and offers good gaming performance with a just-super ceded chipset), or a top-end graphics card that will cost you about $700 - $1000 (which offers a the very latest, fastest chipset, but is being sold at a premium for the privilege).

If you decide to go for the latter two options, you’ll also have to choose between one of the two major graphics chip makers: NVIDIA or AMD (formerly known as ATI). NVIDIA does not make its own graphics cards – it sells card designs to other video card manufacturers, who manufacture them. It doesn’t matter too much which manufacturer you choose – they all produce the reference NVIDIA design. AMD does make its own cards.

The two companies are constantly overtaking each other in the speed stakes, so the best thing to do when choosing a graphics card is to check out the latest card reviews and comparisons in computer magazines and websites.

One really important thing to check, though, is the connectors on the card. There are three main types: VGA (the oldest, analogue connection standard, designed for CRT monitors, but works with many LCD monitors as well), DVI (a fully digital connector used on most LCD monitors and some plasma and LCD TVs) and HDMI (the latest home-theatre connector found on newer Plasma and LCD TVs.)

Most people will want to go for a card that includes both DVI and HDMI so they can connect to an LCD monitor and potentially to a plasma/LCD TV. However, if you have a CRT monitor (or older LCD monitor), you’ll need to get a card with a VGA port.

If you are planning to use a very large screen such as a 30” display, you may need to get a card that has two DVI connectors on the back, or one that has a single DVI connector that supports “duallink” – a cable with a single DVI port on one end and two DVI plugs on the other end. This is because the 30” monitors and above generally need two DVI feeds at once to supply the picture to them.

CD / DVD drives

DVD burners are now so cheap, there’s no real point in getting a CD drive in your PC any more. It’s so useful to be able to backup files to the larger storage capacity of recordable DVDs – 4.3GB vs only 0.65GB on a CD.

One thing you may want to consider is whether it’s worth investing in a high-definition optical drive, such as an HD-DVD or BluRay drive. At the time this article was written, the jury was still out over which format would prevail in the tense standoff between the two camps, so most people are holding off buying for the time being.

Additionally, high-def drives cost over a thousand dollars, and the recordable media costs over $50 per disc, so it’s clearly still prohibitively expensive.

Sound

Most motherboards come with very good on-board sound nowadays. The only people that need to buy additional sound cards these days are gaming enthusiasts who want the very best possible multi-channel surround sound.

Our recommendation in most cases is to buy your PC with the standard motherboard sound first, see whether it’s good enough, and if you want better, to add a third-party sound card later.

Connecting your desktop at home

Most motherboards come with inbuilt gigabit Ethernet networking, for very high performance file transfers over a wired network. But increasingly, people are appreciating the convenience of wireless networking.

Although wireless networking can easily be added to a desktop PC later via an add-on card or a USB adaptor, it’s worth checking whether it’s possible to get a PC with it built-in. This will keep your card slots free for other things.

If you are buying wireless networking with your PC, try to get one that has draft 802.11n support. This will be compatible with older types of networks such as 802.11g and 802.11b, but if you do install a draft 802.11n network at home, you’ll get much better file transfer speeds between the different computers on your network. On the older networks such as 802.11g, transferring a TV episode from one computer to another over the wireless can be a tortuously slow experience – it could take half an hour, for example.

Choosing a modem, monitor, keyboard, mouse

Older desktop PCs used to come with a dialup modem built-in, but that’s very uncommon these days because most people getting a powerful new PC want to use broadband. Broadband modems are always external to the PC, usually plugged in via Ethernet or USB (Ethernet connected models are much better as they do not need software or drivers installed on the PC.) Although the computer shop may be able to sell you a modem, it’s not always a good idea, unless you’ve spoken to your ISP first and found out exactly what kind of modem you need. Generally, buying a modem from the ISP (or at least the same model of modem) is a good idea because if you need to ring up and troubleshoot connection problems, they’ll be better able to help you with modems that they supply.

Choice of monitor is tougher Suffice to say, flat-panel LCDs are the way to go these days as they’ve come down to very affordable prices, and don’t take up as much space or consume as much power as the older style CRT monitors.

When choosing your keyboard and mouse, it’s really worth not skimping on them. Many computer shops can supply a cheap mouse and keyboard, but while a cheap keyboard can be OK, do spend a little bit to get a good mouse. You’ll want to budget $50 - $100 for a Logitech or Microsoft mouse. It’s better to go for corded rather than wireless keyboards or mice, as you can run out of batteries quite quickly, and there’s nothing worse than having to go foraging for batteries right at that crucial moment when you just want your keyboard or mouse to work.

Planning to use an old printer / scanner / monitor / Other?

The latest PCs generally only have newer types of connectors for external devices, such as USB for peripherals, DVI for monitors and Ethernet for modems. If you have an old device like a printer that only has a large 25-pin Parallel port on it, or keyboard/mouse with the old circular PS/2 connectors, or a monitor with a VGA plug, be sure to tell the PC retailer so they can recommend a PC to you that has the appropriate connectors.

Also, be aware that if you’re buying a PC with Windows Vista on it, you may not be able to get compatible driver software for your older devices. Windows XP will be available until June 2008, so if you are planning on using older devices, that’s a much better choice of operating system.

If you have a video camera, you’ll probably need to get a Firewire port in your new PC. Most video cameras use this port, though some now come with USB ports or even memory cards that can be removed and plugged directly into a card reader on your PC