Thinking inside the box – Just what are the bits inside your PC?

If you want to build a PC, then you need to understand the bits needed to put it together. The basics are:

    • A case. This can be a full size tower, or mini-ATX, or even small form factor (SFF). The case size is important, as the interior volume will dictate how many components you can fit inside. Which one you need to choose is going to be dependent on what you want the machine to do and therefore what components you will add to it. Buy an SFF and find that in a year’s time that you buy a game that needs extra RAM to run, but you don’t have any spare sockets then you are going to have a problem!
    • A power supply. This needs to be powerful enough to provide usable power to all of the other components you decide to use. It is always a good idea to provide some headroom in your calculations, as you may want to upgrade or add further components later (unlikely to happen if you go down the mini-ATX or SFF route).
    • A motherboard (MOBO). This is the circuit board which will allow you to plug in everything else to make it work. There are many manufacturers who will generally produce a wide range of boards, each with particular characteristics, and each will be designed for one particular brand of CPU (AMD or Intel). Which one you choose will be a matter of personal preference rather than a particular need, as for the most part, the CPU’s will do largely the same thing. It is only when you need a very specific task carried out that you would need to consider the intricate variances between manufacturer architectural design.
    • A Central Processing Unit (CPU). This is the brains of the operation. The CPU carries out the task of processing all of that code so that you can make the mouse move room one side of the screen to the other. Of course that is an extremely narrow view of what this component does. These days they are multi-core, multi-threading beasts which make sure that everything that you need done, gets done. There are two main manufacturers. AMD and Intel. The CPUs they produce are made using slightly different processes and designs to achieve broadly the same tasks. They are not however interchangeable. You cannot use an Intel CPU on a mobo designed for AMD processors, and likewise AMD will not fit an Intel based mobo. These differences are known as socket variants, and are something you need to understand (at least that the difference exists!) if you want to build your own machine.
    • Random Access Memory (RAM). This is what allows the machine to carry out the processing it needs to do. The CPU will actually crunch the numbers, but to do so it needs to utilise information stored elsewhere (see HDD below). This is where RAM comes in. This is a silicon chip which acts as a file retrieval system for the processor. It gathers and stores the information needed by the CPU, and is used as the processing speeds are so enormously fast that direct reading / writing to and from the HDD by the CPU would be impossible. RAM is volatile memory, so once the machine is powered down, the RAM no longer stores any information. It’s purpose is to facilitate getting information between the HDD and the CPU.
    • Hard Disk Drive (HDD). The HDD is where everything is stored. When you save a photo, or run a program (or app) the HDD is where the information comes from. The CPU takes the information, processes it, and displays it via the GPU (see below). There are different types of HDD. The most recent incarnation is the Solid State Drive (SSD). This utilises chips similar to RAM to store information. The benefits are the small physical size of the drive, and the fact that there are no moving parts to break down. High cost per Gb of storage is the main downside of using SSD. The most popular type of drive in use is the mechanical drive. This consists of a number of magnetic platters which spin inside a housing. While the cost per Gb is lower than SSD, they are noisier and produce more heat (thereby using more power). There also hybrid drives called SSHD. These are a mechanical drive with a small SSD included. The SSD portion is used to store the most accessed programs.
    • Graphics processing unit (GPU). The GPU is used to display the GUI (graphical user interface) which is simply how a program looks on the screen. For most programs, this is a fairly basic static screen, with not a lot of moving pixels. The amount of processing to be carried out by the GPU is therefore quite small. Most decent motherboards will have a small built in GPU, which can handle most basic applications. They will even allow casual gamers to play without any noticeable depreciation in user experience. If however you are editing video files, or playing graphics intensive games then you need more processing power. For these instances, you will want to add a dedicated graphics card. For lower end cards, expect to pay up to GBP50, for mid range up to GBP150 and higher end cards can be anything at all. Some have been on sale recently for GBP4000 or more. If you need one of those cards, chances are you’ll already know all of this though!

    • Other items you may wish to add. There are all manner of additional things you can get. Card readers, DVD / Blu-Ray drives, information panels, sound cards (like a GPU, but processes audio rather than video). Any of these (or indeed other items) would be a matter of personal preference rather than necessity.

If you do decide to go down this route, then you need to plan carefully. You need to ensure that the mobo and CPU you choose are compatible. The RAM needs to be consistent with the clock speeds offered by the mobo. How much RAM will you need? That will of course be dependent on the tasks you expect to do. That should always be your starting point. What is it that I want this PC to do? Once you know the answer to that question, you can then research just what specification you actually need.