This guide is intended to give a simple explanation of what to consider when buying a personal computer. The audience is computer novices or people who have no special interest in what goes on inside a computer as long as it performs the tasks they need.
1. Key Questions to Ask Yourself
There are two important questions that must be answered before settling on a specific computer to purchase:
What will I use the computer for (now and in the future)?
What is my budget?
2. The Basic System
There are a few components that every computer you consider must have so it is important to understand their purpose and how the will affect the performance of the computer you buy.
2.1. The Processor or CPU
The processor is the component that performs virtually all of the computation and controls the behaviour of most of the other devices. The most common processors are Intel's Pentium and Celeron family and AMD's Athlon and Duron. The crudest measure of a processor's power is its "clock speed", given in Megahertz (MHz) or Gigahertz (GHz, 1GHz = 1000MHz). These are the figures that will appear in advertisements. Generally speaking, the faster the clock speed, the faster the computer will be.
The highest speed processors available at any time tend to be disproportionately expensive, so most people tend to buy a slightly slower system.
2.2. Memory or RAM
RAM is the fast memory that the computer uses to temporarily store information for the tasks it is performing. Unlike the hard drive, RAM relies on power being supplied to retain information. When you switch the computer off the information is lost (but don't panic, it can be kept on the hard drive). The size of RAM is measured in Megabytes (Mb) and, as with processor clock speed, more is usually better.
2.3. Hard Drive
The hard drive is a magnetic storage device that can hold programs and information when the computer is turned off. Information is exchanged between the memory and hard drive according to the needs of the tasks being performed (remember RAM is fast so the processor can find information quickly there). The size of a hard drive is measured in Gigabytes (Gb) and, again, more is better.
The monitor is the device that displays information from the computer in the form of windows, icons, images and text. There are two principal types of monitor at present: CRT monitors (the ones that look like televisions) and LCD monitors. Advertisements will quote monitor sizes which is the distance measured across the diagonal of the screen in inches and the resolution in dots per inch. Larger screens can be useful for working with graphics or for desktop publishing.
2.5. Graphics Card
The purpose of a graphics card is to present information in a visual form on the monitor of the computer. The specification of the graphics card will affect the resolution that can be displayed on the monitor and the "refresh rate" of the display. The refresh rate is the number of times per-second that the screen is re-drawn - a high refresh rate produces a flicker free display.
3. Choosing A Type Of Computer
There are two main types of computer available on the market: IBM compatible and Apple Macintosh. They both come in two forms, desktop or laptop.
3.1. IBM Compatible
The most common computers are IBM compatible (although they may be manufactured by someone other than IBM). The advantage of choosing an IBM compatible is the range of software available and the commonality with other computers (although this is less of an advantage). The term "IBM compatible" means that the computer conforms to a de-facto standard ensuring that a range of industry standard components (eg. sound cards, graphics cards etc.) can be incorporated into the machine.
3.2. Apple Macintosh
The Apple Mac is the next most common personal computer and is manufactured exclusively by Apple. There is a smaller range of software available for Macs so make sure you check that the software you plan to use is available in a Mac version.
3.3. Desktop Versus Laptop
The major advantage of a laptop is its portability. This will be the most important factor in your choice if you need to use your computer in different locations such as libraries, at home and in the office or trains. The disadvantage of a laptop is that it is usually a lower specification for a given price and the possibilities for upgrading are more limited than a desktop. Laptops often have a shorter useful lifetime than desktops, partly due to their lower specification but also due to the fact that their nature means that they take more punishment (vibration/knocks) which can cause components such as hard drives or screens to fail.
4. How Much Memory Do I Need?
New machines come with at least 1Gb as standard now. Memory is cheap at this time so add as much as you can afford, especially if you are doing image editing. As a rule of thumb 1Gbb is the absolute minimum you should be considering now, but buy at least 2Gb if you can afford it. Packages like Adobe Photoshop really benefit from large amounts of memory. Memory is one of the speed bottlenecks and adding more is one of the most cost-effective ways of improving an entry-level computer's performance.
5. Choosing The Size Of Hard Disk
Hard disks are also cheap so buy as big as you can afford. You may find that a 500Gb disk costs hardly any more than a 200 Gb one. If you want to cut corners here bear in mind that many software packages need hundreds of megabytes of disk space. Add up the amount for all of the software that you are going to install and leave enough room for your data.
New computers will come with a manufacturer's warranty. The level of this warranty and any associated support will vary greatly. Some manufacturers will only repair faults within a year of purchase and require the machine to be returned to the manufacturer. Others will offer on-site repair (typically for the first year). Warranty periods may be up to as much as 3 years.
It is worthwhile checking to see if anyone you know has experience of support from the manufacturer you are considering.
7. Upgrading Later
Choose a machine that can be upgraded but remember it is more expensive to add extras later. The most common upgrade options are a faster processor, more memory and additional hard drives. Important questions to ask are: what is the maximum processor speed that can be put in this machine? How much extra memory will it take? Most machines will take at least one additional hard drive, but ask anyway for peace of mind.
8. Don't Forget To Budget For Software
Check what software comes with the machine. Typically this will be at least the operating system and possibly some basic packages such as a word processor and spreadsheet. If there is a particular package that you intend to use, don't forget to add this in to the cost of purchasing. Some software you may need will be available at no charge so investigate this before making a purchase. Some software you need may be available at an educational discount so look at the pricelist in the IT Services shop.
One item of essential software that you should buy is a virus-checker. A virus checker is not a guarantee that your machine will be safe from attack but it will offer protection from known viruses.
Make sure that you keep the disks that your software comes on (and copies of the license keys for the installation). These are as much part of your computer as any of the hardware and they are evidence that you have legal copies of the software. You will need these disks if anything goes wrong with your computer and the software has to be re-installed.
9. Off-The-Shelf Or Built To Specification
Computer outlets such as PC World or Dixons supply ready built computers which gives you the option of leaving the shop with your computer the same day. Mail order suppliers tend to build machines to specification, allowing you to customise the machine to your requirements but the disadvantage is that there will be a build/delivery period that could be several weeks long.
10. Second-Hand Is An Option
Take care if you choose this route - suppliers warranties are usually no more than 3 months, Private sales are unlikely to have any guarantee. Second-hand machines are often underpowered for current software.
11. The Operating System
New computers typically come with the operating system pre-installed. The manufacturer may offer some choice of which operating system is installed. If you intend to use a particular software package, make sure that you choose an operating system that the package supports.
12. And Finally...Maintenance
When your manufacturer's warranty expires, it is possible to continue to have support if anything goes wrong with your computer. IT Services offers a maintenance service to cover a wide range of computing equipment at a modest annual cost.
13. Last Words Of Wisdom
Whatever computer you buy, make sure you take regular backups of crucial data (to recordable CD or USB Flash Memory (Pen) drive) and make sure you update your virus checker very regularly.