What is Inside Your Computer? No, It’s Not Magic.

We regularly recommend replacement parts to our clients, and in most cases when we start describing computer components, we end up just talking to ourselves. We have chosen some of the most important components and defined them so that you can have a more complete understanding of the machines that you use daily.

Common Computer Components


The computer case is the enclosure in which all the other components are mounted (duh). The case is a very important component of the computer because it determines how many internal drives (Hard Disks, Floppy Disks, and Optical Disks) you can mount, the effectiveness of airflow, and cable management options. One of the major causes of hardware failure is heat. A fantastic case that has had all of its components installed neatly and properly will have superior airflow, thereby minimizing stagnant air pockets. The more air that can freely move through the case the cooler all of the internal components will stay.


The motherboard is the backplane through which all other computer components communicate. The motherboard itself houses the CPU, Memory, Disk Controllers, and Expansion Slots (for connecting other components like NICs, Graphic Accelerators, and Sound Cards). Because of its complex and fragile nature the motherboard is always a suspect when the computer starts acting strangely. Unfortunately it is nearly impossible to isolate a malfunctioning component of a complex motherboard and replacement is usually a faster and cheaper alternative.


The CPU (Central Processing Unit) or ‘Processor’ is usually considered the brain of the computer. Almost all instructions that the computer will execute will be executed by the processor. There are only 2 major vendors for CPU’s, Intel and AMD, and they come in a variety of flavors ranging from the economical and energy efficient chips that are usually found in cheaper business computers to the high-powered, energy hogs that are found in modern gaming machines.

Hard Drive

The hard drive is the main storage location for data in today’s computers. The traditional hard drive is made up of multiple ‘platters’ that store magnetic ‘bits’ that represent the 1’s and 0’s of the binary language that computers communicate in. These platters are accessed by a mechanical arm that can read and write the ‘bits’ to the platter. A newer style of hard disk is known as the Solid State Drive (SSD). This type of drive has no moving parts, which makes it more durable and reliable. However, Solid State Drives are still not commonly used in computers because they are more costly and they have a lower capacity than traditional hard drives.

Optical Drive

Are these even used anymore? CD, DVD, and Blu-Ray drives are all classified as optical drives. All of these drives use various lasers to ‘burn’ information into plastic disks for long term storage. The different types of optical drives have different storage capacities with CD’s being the smallest and the new BlueRay being the largest. Although optical storage does not match the capacity of internal or external hard drives, it is far more reliable as long term storage. A DVD disk that is kept free of scratches and out of heat or moisture will last at least 50 years!


Memory or RAM (Random Access Memory) is the temporary storage location for all data being processed by the computer. Reading and writing to the hard disk is very slow when compared to reading and writing to the RAM. The maximum amount of memory that you can install into a system is determined by the operating system that computer is running. A standard Windows XP professional workstation has 1-3 GB of RAM. Information written to the memory is only valid as long as the power stays on, as soon as the computer resets or turns off all data in memory is purged.

Graphics Accelerator

More commonly referred to as the ‘Video Card’ or GPU, the graphics accelerator is the component responsible for rendering all of the visual output you see on your monitor. The technology behind the latest graphics accelerators changes almost monthly with new products being released all the time. High end graphics accelerators are almost mini computers themselves, containing their own processors and memory that can rival the performance of the main system components. Why? Well with all of the computing required to render HD graphics, the graphics card does all the heavy lifting for video leaving the CPU free to do all of the other necessary computing.

Network Interface Card

More commonly referred to as the NIC (pronounced “nick”), this device is what is responsible for all of the input and output to and from the internet and your office’s network. NICs come in various speeds (10, 100, and 1000 mb/s), but the functional speed is always determined by the routers, switches, and hubs that make up the network. In most computers the NIC comes ‘Built-In’ to the motherboard, but you can buy regular expansion card NICs like the one pictured to the right. NICs come in wired and wireless configurations as well. To successfully connect to a wireless network you need to have a wireless NIC installed in the computer and a Wireless Access Point (WAP) to connect to. These days, almost all laptop and notebook computers come with a wireless NIC built in.

Power Supply

Probably the most overlooked and most easily damaged component of a computer is the power supply or PSU (Power Supply Unit). The PSU supplies power to the Motherboard, Hard Disks, Optical and Floppy Drives, and Graphics Accelerator (If necessary). PSU’s are rated by how many watts they can put out at any one time. You can see the PSU on the back of your workstation, as it is where the power cord plugs in to the computer.

Hopefully this article has helped to differentiate between some of the major components of the computer. Stay tuned for future articles discussing the different peripheral devices that are commonly found attached to our workstations.

Dean LentzIT basics