Choosing a PC - What To Look For

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Introduction

Buying a PC can be a minefield. There is a huge array of specifications to consider, from the CPU to the memory, the hard drive and the motherboard, amongst many others. The exact same specifications can be on sale for a range of prices for the same reason you can buy a box of ASDA Corn Flakes or a box of Kellogg's Corn Flakes: branding and quality.

To find your way around, we present this guide to what to look for in a PC. We hope you find it useful.

Desktop or Laptop?

Laptops are becoming incredibly popular these days, and with good reason. They offer a great deal of flexibility, and with the growth of wireless networks and 3G phone connections, they allow you to surf the net almost anywhere. However, the trade-off is that every time you buy a laptop, you have to buy a new screen, which increases the cost. Components are also more difficult to source for a laptop, due to the smaller size, and that increases the price further.

£350 may buy you a budget laptop - but for the same price, you could buy a very decent specification desktop PC. Laptops are also prone to accidents, and anecdotally suffer a lot more with faulty power supply cables, short-lived batteries and overheating if poorly designed.

The choice is yours: if you travel regularly and need your computer with you, then a laptop is a no brainer, an essential. Otherwise, you should think very carefully before deciding to buy one.

Or maybe a Netbook?

2009 is seeing the rise of the netbook - small laptops running on lower power and more efficient components. Some of them do not come installed with an operating system, others come with a variant of Linux, but most are now being sold with Windows. Netbooks are excellent for computing on the move, but generally their smaller screens and lower performance will leave the average user looking for more.

What processor?

The headline grabbing figure, particularly on eBay, is the processor or CPU. Beware of sellers who describe a multi-core machine with deceptive language. A three-cored 3.0GHz CPU does not give you 9GHz of processing power. Neither does a dual-cored 2.5GHz CPU give you 5GHz of power. I have seen a number of computers described in such a way

Generally the higher the processor speed the better, but you must also consider the levels of L1 and L2 cache. This is exceptionally fast memory (particularly L1) that resides wholly on the CPU. CPUs only provide a very small amount of it (especially in comparison to your system memory), but the more of it, the better. L1 and L2 cache, however, is expensive.

How L1 and L2 cache combine with processor speed is crucial. Budget ranges of processors may provide a decent GHz rating, one that may even be favourable when compared with a much higher-end processor, but they may have much less L1 cache, for example. Once again, this is a trade off that the average user must decide.

Nevertheless, even budget processors, particularly the Intel Celeron range, provide excellent performance now compared to when they were first launched, particularly if you do not use your PC for gaming.

Memory

Just like processors, memory has a great deal of variety, and, just like processors, memory has a speed rating. The minimum you should look for in a PC today has to be what is known as DDR2 memory.

However, it doesn't end there. Memory speed is usually given in two numbers, for example, DDR2 800 MHz/PC2-6400. This particular speed of memory is a very good choice for almost all PC usage. Lower ratings of 667 MHz/PC2-5300 are acceptable, but anything below this should be avoided.

PCs on the high street frequently do not tell you what speed the memory is, preferring instead to concentrate on size. But because the high street neglects to tell you the memory speed, they can get away with installing inferior quality chips just because they can fool you with a high memory capacity. Buyer beware!

1GB of RAM is the absolute minimum, but 2GB is recommended, especially for Windows Vista, and 4GB+ is optimum for gaming. However, to achieve any memory of more than 3.5GB, the computer needs to be running a 64-bit version of operating system (more on that later!).

A further complicating factor is that the best performance from memory usually comes from installing memory in pairs in order to gain the maximum benefit from the dual channel specification. That is to say that if you want 2GB of memory, you should install two identical 1GB chips. There is no guarantee that a high street PC will have installed the memory in such a fashion. If they haven't - and, for example, it says it's a 2GB machine but there is only one stick of 2GB memory in it - then the machine will be needlessly crippled because of poor construction standards.

DDR2 is also available in 1066MHz/PC2-8500 and slightly higher, but bleeding edge machines now have DDR3 memory, the next generation, starting at 1333MHz/PC3-10666. There are faster chips, going up to 2000MHz/PC3-16000 - but these are expensive and, at time of writing, are unnecessary for the simple reason that the CPU cannot keep up (due to a limitation of their FSB speed that we don't have time and space to cover). Suffice to say that, for most purposes, the top end of DDR2 and the start of the DDR3 market is a good place to be for the vast majority of PC users.

Hard drives

Unfortunately for the poor downtrodden consumer, it doesn't get any easier here. Superficially it may look good to be getting a hard drive with huge amounts of space, but the technology of the drive interface is important, as is the spin speed, and the onboard cache of the drive.

Most computers should now come with a SATA hard drive. If they don't specify, avoid them, as it invariably means they will be using obsolete IDE/PATA technology and will provide poor performance. Ideally, you're looking for SATA "2.0" 300 - which is slightly faster than the original SATA specification.

Spin speed is measured in revolutions per minute (rpm) - and you should be looking for at least 7,200rpm. Cache memory is measured in MB, and though there isn't a great deal of difference for a PC with only one drive, it is slightly more advantageous to have at least 8MB of cache on a 160GB drive, 16MB of cache on a 320GB drive, and so on in similar proportions.  

Depending on how much multimedia you download to your PC (music, videos, photos) you should be looking for at least 160GB hard drive space, but 320GB is now common, and drives are now available with well over 1,024GB (also known as a terabyte). Bear in mind, though, that even if you run low on space, you can now buy extremely simple large capacity USB drives that you can plug into your computer and store your photo albums on, for example. Some of these drives may even use a variant of the SATA technology (called eSATA) which will allow you to achieve speeds as quick as your internal hard drive - though your computer needs to support it.

Once again, these variations in the technology are often overlooked by high street PC retailers. It is extremely easy to save money by purchasing low spin speed, low cache, hard drives, especially if their size is still large enough to deflect attention. Bear in mind too that, on a PC, the major limiting factor to higher performance is not the CPU, or the memory, but the hard disk drive. Failure to invest wisely on this part of the PC could render even the most expensive other components useless.

Motherboard

The motherboard is an essential component, with a large number of manufacturers. It can be an extremely basic model with limited options for expansion (few USB ports, no PS/2 connectors, no eSATA, for example), or it can have a huge range of abilities. More likely it will be somewhere inbetween.

A decent motherboard is a pre-requisite for the simple reason that every PC component is connected to it and hence has to interface with it. If the motherboard can't keep up with the CPU, or the memory, then it will be forced to slow everything down to the speed of the weakest link.

Motherboards have a great deal of variety in terms of the components on them. A good board is likely to be in the price range of £60-80, though there are notable exceptions in the budget models - for instance I have seen motherboards as low as £40 that have almost all the average user needs and more, and do the job surprisingly well.

Most motherboards now come with onboard sound, meaning you don't need to buy a separate sound card. They may also come with onboard graphics support, more on that in the following section. But, as you might expect, if they are provided, they are nothing special, but do the job for the average non-gamer. Otherwise, for those with specialist needs (audio lover, multimedia editing, extreme gaming) - you probably will need to buy a separate component.

Graphics card

The arena of the graphics card is quite possibly one of the most complicated because of the vast range of manufacturers. Though most cards are either ATI or nVidia at the heart, the card itself, and the remaining technology, is usually made by someone else, who themselves use their own methods and components.

For the average user, not bothered about gaming, this part of a PC can generally be overlooked as the retailer will supply a PC with a built in graphics controller. They are totally inadequate for gaming, but should support the various visual effects supplied by Windows Vista's Aero scheme.

Gamers, on the other hand, will be looking for something like an nVidia GeForce 9800GT or an ATI Radeon HD 4850. Good varieties of these are usually in the region of £100.

Operating system

Earlier we referred to computers with more than 3.5GB of memory needing a 64 bit operating system. This is because the previous technology of computing (32-bit) has run its course and has now been replaced. However, at the moment we are in something of a transition period, with 64-bit processors being sold on computers running a 32-bit operating system - the consequence of which being the processor does not reach its full potential.

For the most part this is not a particular problem right now, but it is if you have 4GB of memory, for example, as your shiny new PC will only tell you it has 3.5GB (or worse, 3GB) if you are running plain Windows XP or Windows Vista. To get the full benefit, you must run Windows XP 64-bit/x64 edition (though I would not recommend this for reasons of poor compatibility with modern components) or Windows Vista Home Premium (or above) 64-bit edition.

More generally, however, you should probably be looking for a minimum of Windows Vista these days, as Windows XP is about to become extremely outdated with the imminent launch of Windows 7. The more adventurous power user may wish to look into Ubuntu - a free, powerful operating system that is looking more and more appealing as a replacement for Windows as the months go by.

DVD drives

Most machines these days come with, as a minimum, a DVD/CD drive which also can write as well as read. There isn't a great deal of variety in this field apart from the speed of the writing, or the ability to "write" on the cover of the disk to create a nice image (a technology known as LightScribe). For the average user, take a break from surfing specifications and accept that what you're being offered should do the job!

So what is a good machine these days?

To round it all off, the average user, non-gamer, might be looking for something like this for the three key components:

  • Processor: AMD Phenom X3 Triple Core 8650 or Intel Core 2 Duo E7400 2.8GHz

  • Memory: 2 x 1GB DDR2 1066MHz/PC2-8500 or 800MHz/PC2-6400 (an identical pair)

  • Hard drive: 320GB SATAII 16MB Cache 7200 RPM

Motherboards should generally have enough bells and whistles to keep you satisfied (e.g. front panel, easy access, USB and headphone plus microphone sockets), support dual channel memory and have sufficient graphics and sound capability. DVD drives should give you the ability to write too.

That is not to say that a lower specification processor could not do the job. A basic E1400 2.0GHz dual core Intel Celeron achieves 4.9 on the Windows Vista "Windows Experience" benchmark test. It really does depend on what you need from your machine - and for the casual user, a processor like that would be more than adequate.

Conclusion

This has been something of a whirlwind tour of the realm of the PC component. We have covered each of the critical ones in turn and given a brief run down of the kind of thing you should be looking for. Inevitably I have overlooked things (e.g. FSB), sometimes necessarily for the sake of simplicity, and perhaps otherwise because I forgot about it - in which case I apologise - but I think, broadly speaking, this is enough to give you a good general overview of PC specifications.

It can be an exceptionally confusing world, and the fast pace of change means you need to stay on top of what's going on if you want to have a hope of putting together the components in a way that maximises their performance. A PC can only be as good as its weakest link - and so the combination of all the above is what actually delivers the end product as you stare at your monitor, not the individual parts themselves.

The key point to remember is this: the high street retailers gloss over many key factors when describing a PC. The question that you must ask yourself is why? Do they have something to hide? In my experience, they do. They conceal poor speed on a memory chip, for example, by distracting you with masses of hard drive space that you might not actually need.

As always with these things, as the old saying goes, you pays your money and you takes your choice. It's just with PCs you need to be reasonably well informed in order to make a good choice. And if you're not informed, then you might as well ask a random number generator to pick your computer for you.

If you like taking expensive gambles, then good luck to you! For the rest of us, a little research really will go a long, long way...

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