What's Inside a Desktop Computer?

Introduction

This guide will describe the inner components of a desktop computer. Many people today are not entirely sure how computers work or what components there are in modern computers. This leads some to believe that some certification or degree is required to understand how a computer works or is built. However, building a computer is much like building a creation with Legos. A desktop computer is a stationary computer that is often connected to external peripherals, such as a keyboard, mouse, and monitor. A modern desktop computer usually consists of a case, motherboard, CPU, HDD, RAM, GPU, and power supply. This guide will help to understand what a desktop computer is composed of.

Case

Figure 1: The Corsair Air 540 Case

Many people believe that while computer cases may look different on the outside, they are all the same on the inside. While this may appear to be true, there are actually several different computer

case form factors. There have been many form factor specifications created in the past. However, today only three are still commonly used. These are the Advanced Technology eXtended (ATX), Micro ATX (mATX), and Mini-ITX form factors. Each of these form factors has its own dimensions in order to fit all of the needed components. Figure 1 shows a popular computer case made to fit ATX and Micro ATX motherboards. The computer’s motherboard also depends on the form factor of the case, as it governs the size of the Printed Circuit Board (PCB).

Motherboard

Figure 2: A motherboard with labelled connections

The motherboard’s main function is just what the name suggests. As Figure 2 shows, the computer’s motherboard serves as a host to which all other components plug into. Motherboards come in all shapes and sizes depending on the type of components that can be plugged into it. This is why the case’s form factor is important. If the form factor of the motherboard does not match the form factor of the case, then the motherboard will not fit into the case properly. The only exception to this is the mATX form factor, which can be properly installed in an ATX form factor case. This is like a new stereo system having both a CD and tape player, but the old tape player not being able to play CDs. ATX form factor cases have mounts for mATX motherboards, but mATX cases do not have mounts for ATX motherboards. Another important specification to be aware of on the motherboard is the Central Processing Unit (CPU) Socket specification. This will narrow down your choices as to which CPU you can use in your computer. Read more about why this is important in the next section.

Central Processing Unit (CPU)

Figure 3: A pair of Intel CPUs

The Central Processing Unit, or commonly referred to as the CPU is the brains of the computer. Its primary function is to manage all other parts of the computer and to process all information. Just like an engine in a car, the CPU has many different models and generations with varying degrees of power. When a new generation of CPU is released to the public, there is a hardware change in the socket on the motherboard that makes it impossible to use older CPUs. This is why it is so important to make sure that the socket specification on the CPU matches the one on the motherboard. It is similar to trying to plug in an American appliance into a wall outlet in the UK without an adapter. It simply won’t work.

Storage

A computer has many types of memory. However there is only one type of memory that users will interact with, and that’s non-volatile memory. Non-volatile memory is a technical term for any memory that will persist even after the computer itself is powered off. Today, the main type of non-volatile memory is the hard drive. The hard drive (HDD) is a storage device that stores large amounts of data on metal platters that commonly spin at either 5400 or 7200 RPM. When researching which hard drive to buy, it is important to see what connector it uses. For most desktop/ internal hard drives, the connector will use the SATA (Serial ATA) standard. This is a connector that is included on every modern motherboard. In addition to the SATA connector, there is a power connector on the hard drive, and a compatible cable on the power supply of the computer.

Random Access Memory (RAM)

Figure 4: A stick of desktop RAM

Random Access Memory, or simply RAM, is a type of volatile memory. This is not to say that it is unreliable, but that when the computer is turned off, the RAM loses the data that is stored on it. When compared to a hard drive, RAM is immensely faster. Comparing RAM to hard drive speeds is like comparing the speed of a Bugatti to that of a snail. When data is loaded from the hard drive, it is loaded into RAM so that it can be accessed and modified a lot faster than if it was constantly being loaded off of the hard drive. Today, there are two types of desktop RAM: Double Data Rate Type 3 (DDR3) and Double Data Rate Type 4 (DDR4). RAM is governed by the specification on the motherboard, with no compatibility between versions.

Graphics Processing Unit (GPU)

Figure 5: An ASUS GTX 970 graphics card

Another component commonly seen in desktop computers today are Graphics Processing Units, called video cards or GPUs. While most modern CPUs have the functionality of processing graphics by themselves, the processing power does not compare to that of a dedicated graphics card. Having a dedicated graphics card allows the computer to be able to process most graphics-related calculations a lot faster than a CPU can. Video cards are mostly marketed to those who want extra computational power to be able to run video games at higher settings and professionals who use special programs that make use of the video card’s computational abilities.

Power Supply

Last, but certainly not least, a computer needs its own specialized power supply. Generally, unless otherwise specified by the case, an ATX power supply is used to power a computer. There is only one detail to look out for when researching power supplies, and that is how many watts it outputs. There are many calculators that can determine what wattage power supply is needed, but most people need a 400W power supply without a video card and 500W power supply with a video card at the minimum.

Bibliography

Corsair. (n.d.). Carbide Series® Air 540 High Airflow ATX Cube Case [Digital image]. Retrieved March 24, 2016, from http://www.corsair.com/en-us/carbide-series-air-540-high-airflow-atx-cube-case

Intel. (n.d.). Intel Devil’s Canyon Processor High-Res Shot [Digital image]. Retrieved March 24, 2016, from http://wccftech.com/intel-devils-canyon-processors-officially-announced-core-i74790k-core-i54690k-march-4-ghz-barrier/

What is a Motherboard - ATX motherboard layout [Digital image]. (n.d.). Retrieved March 31, 2016, from http://www.what-is-my-computer.com/what-is-a-motherboard.html

C. (n.d.). Vengeance® — 4GB Dual Channel DDR3 Memory Kit (CMZ4GX3M2A1600C9) [Digital image]. Retrieved March 31, 2016, from http://www.corsair.com/en-us/vengeance-4gb-dual-channel-ddr3-memory-kit-cmz4gx3m2a1600c9

A. (n.d.). ASUS Strix GeForce GTX 970 [Digital image]. Retrieved March 31, 2016, from https://www.asus.com/us/Graphics-Cards/STRIXGTX970DC2OC4GD5/