In this mini-series of articles we’re going to be taking you through the stages of building your own PC, from sourcing your components, to assembling them, to installing an operating system and then on to actually using your machine.

In this first part we’ll talk about the different components you need and how to make sure that the parts you buy are compatible, but before we get to that it’s important to establish why on Earth you would want to build a PC.

The simple answer is: cost.  Most people will already have a PC at home that they can re-use some of the parts on.  Even if they don’t, with a bit of smart shopping it’s still possible to build the machine you want for cheaper than you would be able to buy it on the high street.  Building your own PC also allows you to get the exact specification that you want, meaning you don’t have to compromise by buying one of the machines that your retailer happens to have in stock that week.

So, first things first, there are a few main components that you absolutely will need in order to make a PC, these are:

• A case – Something to put your computer inside
• A Power supply – to power your computer
• A motherboard – the main circuit board inside your computer, on to which we attach everything else
• A processor – the brain of your computer
• Memory (RAM) – needed to run Windows and applications, as well as edit files.
• A hard disk – used to store your files and programs so you don’t lose them when you turn the computer off
• An optical drive – such as a DVD drive or Blu-ray drive; for playing media and installing programs

There are several other components that you can install, such as TV tuner cards or wireless network cards, we’ll cover these separately at the end of this article.  For now, lets talk about each of the essential parts in order.

Cases

There are many different shapes and size of computer case, but really there are only a small number of variations for how the inside is laid out.  The outside of the case is purely an aesthetic choice; making sure you get the right case for the environment it’s to be used in is important.  But even more important than that is making sure that the inside of the case is suitable for the components you plan to use.  The main standard for the inside of a case is called ATX (Advanced Technology Extended) which refers to the size and shape of the motherboard that’s to be used inside.  Most cases will be badged as either “ATX” or “Micro ATX” compatible, an ATX case will accept pretty much any motherboard that you would purchase, whereas a Micro-ATX case is smaller and will only have room inside for a Micro-ATX motherboard.

When choosing a case it’s important to consider the other components you plan to put inside as well, some of the more expensive graphics cards are physically very large so it’s very important to make sure that the case you buy has enough room inside to house all of your components.  There are also only a finite number of spaces for things like hard disks and DVD drives, so it’s important to check that the case you buy has enough of these slots to suit your requirements.

Power Supplies

Like cases and motherboards, these come in two main standards; ATX and Micro-ATX.  These define the physical size of the power supply in order to make sure that it fits inside your case, so it’s important to make sure you buy the correct size for your case.  Just as important as getting the right size, is making sure that the power supply you get can supply enough power to the other components in your system.  Typically, a small PC with one DVD, one hard disk and no other extras installed will be fine with a 400 Watt power supply, however there are power supplied that can supply over 1000 Watts (1kW) of power.  Supplies like this are only needed if you are powering lots of cards and devices inside your computer, the biggest culprits are high performance graphics cards which can draw 200-300 Watts on their own!

Some cases will come bundled with a power supply, though most will still be either an ATX or Micro-ATX unit.  These units tend to be of a lower quality than units that you can buy seperately and often prove noisy and inefficient.

Efficiency is also a consideration when choosing a power supply, most are now over 80% efficient, but higher numbers are better for the environment so this may be worth a slightly higher price to you.

Motherboards

At this point things start to get a little complicated, but don’t worry; once you establish a couple of things the choices become fewer and differentiating between models becomes easier.

The first thing you’ll need to consider when buying a motherboard is which type of processor you want to use.  There are two main manufacturers of processors for home computers, AMD and Intel, and they never agree on anything!  As such, each manufacturer uses a different size for their processors and differing numbers of pins to connect it to a motherboard.  Choosing which of these processors you are going to use will cut down your choices for motherboards, but the problems don’t end there because both AMD and Intel produce several different sizes of processor, so it’s important to make sure that you buy a motherboard with the correct connector for your processor.

The part of a motherboard to which the processor connects is called the socket, and once you’ve decided on a processor you’ll know what type of socket you need.  The most recent socket size for AMD is called “AM3″, whereas Intel currently produce processors for a few different socket types such as 775 and LGA1366.

Most manufacturers have a compatibility list which shows you which motherboards are compatible with which processors, these tend to be updated regularly so you’ll know if it’s possible to use the processor you want with the motherboard that you have in mind.

Because all of the other parts of a computer connect to your motherboard, it’s important to make sure that it has all the features that you’ll need.  All modern motherboards will have sockets called PCI (Peripheral Component Interconnect) and/or PCI-express.  These sockets are long and thin and are used to connect add-on cards such as graphics cards and wifi cards to your PC, it’s important to make sure that your chosen motherboard has the right type (and the right number) of these sockets available to you.

Processors

As explained above, there are currently two main manufacturers of processors for home computers: Intel and AMD.  Of the two, AMD tend to be cheaper than Intel, but many believe Intel products to be of a generally higher quality.  Whichever brand you choose will have no effect whatsoever on the types of programs that you can run on your computer, both are 100% compatible with one another in terms of operating systems and applications.

The main considerations for a processor are it’s clock speed and the number of cores that it has.  The clock speed is measured in Gigahertz (GHz) and is a measure of the number of processing cycles per second that it complete.  Higher numbers for clock speed are generally better.  The number of cores in a processor relates to the number of processing centers on the chip, historically this figure has always been one, but in recent years manufacturers have taken to putting more cores on a processor as a way to speed up computers.  It’s now common to see processors with two, four, or even six cores.  Like clock speed, more cores is better.

Memory

The type of memory that you need will be determined by the model of motherboard that you buy.  Memory (or RAM) is now almost universally of a type called “Double Data Rate” (DDR) and is split into three standards, DDR1, DDR2 and DDR3.  DDR1 is now obsolete, but DDR2 and DDR3 are still both used in current motherboards.  Your motherboard manual will tell you which standard of memory you need to buy, as well as the type (DDR2 or 3) it will also tell you the maximum clock speed of the RAM you can use (measured in GHz, the same as for processors).

Memory cards are long, thin circuit boards that connect to sockets on your motherboard, most motherboards will have between 2 and 8 slots into which you can install memory cards.  The cards themselves can contain different amounts of memory storage which is measured in Gigabytes (GB’s).  Most common are 1GB and 2GB boards, though boards containing 4GB are also available.  It’s important to find out from your motherboard manual how much memory can be installed in each slot.

Hard Disks

Hard disks are the part of your computer onto which all your data is stored.  It’s screwed inside your case and connects to your motherboard with a data cable, and is fed power from your power supply.  Hard disks are a complex subject and are covered on this site here.  There are two physical sizes, two interface types and two types of hard disk available to consumers.

Of the two sizes, the one that most home computers will need is a 3.5″ model, which denoted the width of the casing of the hard disk.  All 3.5″ hard disks are of the exact same physical size and have the same spacings for mounting screws etc.  The majority of cases are designed for 3.5″ disks.

Of the two interfaces, the most modern is Serial Advanced Technology Attachment (SATA).  99% of motherboards sold today will have SATA ports on them to which you can connect your hard disk cable.  The older standard (IDE) is now being phased out, so IDE disk drives tend to be more expensive and slower.

Of the two types available, traditional rotational disk drives are still the most widely used.  Most computers are still shipped with this type of disk drive as they are cheap and can store a lot of data.  The other type of drive available is called a Solid State Disk (SSD), these work by having memory chips inside the casing instead of spinning disks.  The advantages of these are that they can transfer data a lot quicker than traditional drives, but they are also a lot more expensive and have smaller amounts of storage than traditional disk drives.

With regard to hard disks in general, they are measured in terms of the amount of storage space that they have in the same way as memory chips.  Capacities are measured in Gigabytes and TeraBytes (TB), 1 TB is equivalent to 1024 GB, therefore a 2TB drive has around four times as much storage space as a 500 GB hard disk.  Larger hard disks are generally better as they offer you more space on which to store your programs and files.

Optical Drives

An optical drive is a fancy name for a DVD or Blu-Ray drive inside your computer, it’s named as such because the drive uses laser light (optics) to read and write information from plastic disks.  Most people are familiar with DVD’s and Blu-Ray so I won’t patronise you, DVD drives are almost universal in modern PC’s, whereas Blu-Ray drives are not so common and are generally more expensive because they are the latest technology for optical disks and can hold a lot more information than DVD’s.

For reference, a Bluray drive will also play DVD’s, and both types of drive will play CD’s.

As well as reading disks, some optical drives have the ability to write to disks using a special lazer to burn information on to special recordable disks.  It’s usually a good idea to buy an optical drive that can write to disks so that you can backup information and share your files and media with friends and family.  A drive that is capable of writing information as well as reading it will be denoted with "RW" in it’s name, for example:  DVD-RW, BD-RW.

Optical drives use the same connections as hard disks to connect to your motherboard, SATA and IDE.  As with hard disks, IDE is being phased out, so the vast majority of optical drives available to you will be of the SATA variety.

Other Components

There are many other components that you can buy for your computer.  The most popular of these is a graphics card, in fact in some circumstances a graphics card is essential:  Not all motherboards contain the circuitry to allow you to connect it to a monitor or TV, so a separate graphics card is required in order to use your computer.  Graphics cards almost all use the same socket on a motherboard, which is a PCI-Express socket.  Other components you can buy include sound cards (though almost all motherboards will have this included), network cards (most motherboards have these) and TV tuner cards (to let you watch TV on your computer).  It is important to consider if you’ll need any of these additional components as they can add to the price of your computer and influence your decisions for buying a motherboard dependant on the number of slots available.

Where to Buy Components.

Though high street shops are increasingly supplying components directly to consumers, the best place to source them is still from online retailers.  These sites specialise in stocking a large variety of components which means that you have the best chance of tailoring your computer to your requirements and controlling your budget.  Links to some major online retailers are given below, each offers a vast range of components to ordinary consumers and most have a lot of the information regarding compatibility available to view.

http://www.aria.co.uk/

www.ebuyer.com

www.dabs.com

www.misco.com

www.overclockers.co.uk

In the next part of this series I’ll take you through the assembly of a computer, step by step (and with pictures) so that you can see each of the components mentioned here and how they connect together to form a home computer.

It’s important to realise that although prices will be similar between suppliers, often specific components are cheaper on one site than another, so it’s a good idea to shop around for the best prices.  Do take into account the postage charges though, as these can eat into any money you do manage to save by shopping around.

To move on to part two of this mini series, click here