Inside the Case: A Beginner's Tour around the PC

by Taliesin Coward

For a number of people (and especially, in my experience, Mac users), PCs are something of a mystical box. You push a button, a light comes on, and, somehow or other, things happen. For some people, especially those who view PCs simply as a tool – a means of laying out photos, writing text and checking social media – this is as much as they need (and want) to know. But, if you’re interested in computer games, sooner or later you’ll have to become acquainted with the internals of a PC. Whether it’s simply to know whether your machine is capable of playing the latest and greatest game without grinding to a halt, upgrading or even building your own machine, this knowledge is essential. Yes the information that follows is a bit vague and simplistic, but we all have to start somewhere. So welcome to the beginner’s guide to the PC.

Before we dive into the details of what makes up your PC, there are a few bits of information and abbreviations that will be helpful.

Hertz: a unit of frequency.

1 Hertz = 1 cycle per second.

For PCs, Hertz are often used to measure the speed of the CPU. In very basic terms (avoiding complications of mulit-threading, parallel processing and limitations of coding) the higher the number, the more calculations the CPU can per-second. CPUs are measured in:

megahertz (MHz) = million Hertz. (e.g. the old Pentium II CPUs which ran at 250-450MHz).

gigahertz (GHz) = thousand-million Hertz (e.g. the current generation of AMD and Intel CPUs, clock-in at over 3.7Ghz).

Byte: a unit of memory size (how large a piece of information is). In PCs, used to measure data size and to express storage capacity:

1 megabyte (MB)
= one-million bytes of information

1 gigabyte (GB) = one-thousand megabytes

1 terabyte (TB) = one-thousand gigabytes.

To put this in perspective, the storage capacity of an old floppy disc is 1.44MB, a CD is 700MB, a standard DVD is 4.7GB, and a standard Blu-ray disc is 25GB. Where games used to fit on a handful of floppies, todays AAA games can easily weight in at over 40GB.

Piece by Piece


Also known as the ‘chassis’ (pronounced ‘shaz-ee’), this is the box which houses all the working components of the computer. Its main job is to protect both the computer components, and the user (sadly, more than one person has been killed by touching the internal workings of a PC while it’s been plugged into the mains). It also shields the internals from dust, and help keeps everything cool.

Cases come in a number of different sizes (Full Tower, Mid-Tower, Micro...) and supporting a variety of motherboard form factors – more on that later. These range from plain and simple, to snazzy affairs with glass panels, RGB lighting, and a price range which stretches from under $100 to over $600.

While how much you want to spend on a case is up to you, if you’re building a PC it’s well worth the effort of stretching the budget to get out of the low-end. Unless, of course, you want to house your components in space that’s cramped, difficult to clean, suffers from poor ventilation and too few cooling fans, and has inefficient dust filters; all of which lead to overheating problems. Oh, the cheaper cases can also have sharp internal edges. One of the first computers I built was housed in a cheap $50 case. Boy, was that a mistake. Aside from overheating on hot summer days, I also managed to slice my hand open on its internal frame. Not fun.

Power Supply Unit (PSU)

Self-describing, really. Its job is to take the power from the mains supply and output it in a form your PC can use. These are rated in x-number of watts. The bigger the number, the more powerful the equipment you can run. For example, while a basic word processor would be comfortable with a 500 watt PSU, a gaming rig rocking multiple graphics cards, lighting, numerous HDDs, custom cooling, etc., would need something more in the range of 750-1000+ watt PSU. These are relatively inexpensive, and it’s not hard to find one with a good reputation. The last thing you want is a PSU which is on the blink – this can lead to everything from random system crashes and a flat refusal to boot, to shortening the lifespan of all your equipment.


Also known as a mainboard, this is the central hub of your computer. Everything to do with your computer, whether it’s the PSU, case fans, keyboard, and on-off switch, ultimately ends up connected to here.

Motherboards come in a number of form factors, such as the standard ATX, EATX (a longer ATX board; the ‘E’ stands for ‘Extended’), and mATX (micro-ATX). Motherboards are made specifically to be compatible with particular series or types of CPUs (see below) – you can’t mix and match. Your choice of motherboard will depend upon several considerations, including: what brand of CPU you will be using, what form factor, how many USB connectors and internal connectors you want, and whether you want one which can be overclocked (made to run faster than standard – a consideration for enthusiasts only). The more features, the more pricey.

Central Processing Unit (CPU)

This is the brains of the outfit – a large micro-chip with billions of transistors crammed onto it. This does all the number-crunching which transforms ones and zeros that the computer operates in, into something we can understand and interact with. All the ‘thinking’ your computer does, whether it’s controlling an AI opponent or translating button clicks into commands, is done here. Needless to say, the faster this is the better. One of the first PCs I had a go of contained an Intel 80486 CPU, capable of a massive 100 MHz. Skip forward a few decades, and PCs running at 3.4 Ghz are not uncommon, and even my phone has a 2.2 GHz CPU in it.

When it comes to CPUs, you really only have two choices of manufacturer: Intel and AMD. Constantly vying for top spot, over the years it has invariably worked out that Intel produces CPUs which are faster and more powerful than AMD, but more expensive. AMD, on the other hand, tends to come in at a close second, with comparable performance despite often running at reduced speeds. (Basically, raw grunt vs clever engineering). Which you choose really will depend on how fast you feel you need, what you want to be doing (certain programmes, for example, are designed to work best with particular CPUs), and your budget. For gaming, you really don’t want anything less than an Intel Core i5, or AMD Ryzen 5 2600.

CPU Cooler

CPUs get hot, very hot when they work. To stop catastrophic failure, they need to be kept cool. CPU coolers range from ‘stock’ coolers supplied with the CPU (a no nonsense heatsink and fan array which gets the job done), to large third-party coolers, and liquid cooling systems (if you’re thinking liquid and electronics doesn’t sound like a good combination, you’re not the only one – great when they work, but a disaster if anything goes wrong). In reality, the stock cool will work for most people, and only enthusiasts determined to squeeze every last inch of performance out of their machines will be interested in the latter options.

Random Access Memory (RAM)

If the CPU is the brains of the PC, then RAM is its short-term memory. When you want to run a programme, do word-processing, or anything really, the information is taken from long-term storage (Hard Disk Drive), and then brought into RAM for your CPU to be able to quickly access it. The more you have and the faster it is, the better. In general 16 GB is good, and 32 GB should be more than sufficient. Note that the type of RAM used is determined by its compatibility with the specific motherboard. Also, in terms of performance it’s usually not worth going to the added expense buying super-fast RAM unless you’re trying to get the absolute maximum out of your computer.

Hard Disk Drive (HDD) and Solid State Drive (SSD)

This is your computer’s long-term memory. In general the bigger and faster the better. In HDDs, you have traditional spinning platter drives, where the information is stored on spinning magnetic platters – hence you’ll see an RPM rating as part of the drive’s specs. Unless you want your computer to respond at something other than a snails-pace, make sure to get a HDD which runs at 72,000RPM and has a cache of at least 64MB cache (the more the better).

While the newer, SSDs have the advantage when it comes to speed, they are also wildly more expensive – sometimes costing up to 75 times more per GB than a traditional platter drive. Because of this, a usual arrangement is to have one SSD where you store your operating system to maximise computer startup time, and several standard HDDs where you store your data and games.

Whatever you do, make sure you pick something with a reputation for being reliable, and create external backups of your data regularly; you don’t want the drive to die and take all your hard work with it.

Graphics Card (Graphics Processing Unit/GPU)

Alongside the CPU, gamers regard the GPU as one of the most important, if not the most important, single piece of equipment in the computer. This is what draws all those impressive pictures on your screen: the high definition textures, lighting effect, smoke, rain... in short, everything that you see.

Effectively a specialised miniature computer, graphics cards come with their own discreet processing unit (the GPU) and super fast RAM. For gamers with enough money to invest in just one high end piece of computer gear, this is where the money will go. The faster the card and the more memory it has, the more spectacular looking games the computer will be able to run without stuttering or grinding to an ungainly halt. While less powerful graphics cards can sometimes get the job done and you can get a smooth frame-rate, this will often be at the cost of unappealing graphics which look flat and bland, rather than three-dimensional and full of detail.

As with CPUs, there are really only two brands to chose from: nVidia, and AMD. Similar to the Intel/AMD dichotomy in CPUs, AMD occupies the performance-for-budget end of the market, while occasionally snaffling the high-performance crown, while nVidia is invariably the reigning king of the super-powerful and expensive GPUs.

To complicate matters further, some cards pack extra features. For example, nVidia cards also enable the use of PhysX in some games, which adds realistic physics to the game world, and its latest RTX series has introduced ray-tracing capabilities (while only a limited number of games currently support this technology, the list is growing).


Once upon a time, if you wanted to hear anything other than beeps and whistles out of your PC, you had to install a sound card. Fortunately, today it is standard for motherboards to come equipped with onboard sound. For the audiophile, however, a good soundcard is still a necessity. For your consumer-grade cards, the reigning manufacturers are ASUS and Creative, and their cards range from around $100-$500, depending on the quality of the components and what feattures you want. Note, if you’re going to get one of these, make sure you have high-quality speakers to match or you might as well not bother.

Optical Drives

Last, but not least, we come to optical drives. CD players, DVD drives, Blu-ray burners all qualify. Today, at the very least you’ll be wanting a Blu-ray drive (BD-drive) which has the ability to write data (‘burn’) to DVDs and CDs.


Not the subject of this article, but this includes screens, mice, keyboards, speakers... anything which plugs into the computer but isn’t really a part of it.

If you’re thinking of building a PC from scratch – a subject worthy of its own article, if not whole edition – don’t feel daunted by the number of components. Just remember that the first step is always to choose what CPU and GPU you want. This will massively simplify things, as it determines your choice of motherboard (which in turn determines what RAM you can use), what size case you need (high-end GPUs can be more than 11” long), and how large a PSU you require. ■

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