What Is Computer Hardware?

Computer hardware includes all the physical parts that make up a computer, such as the central processing unit (CPU), random access memory (RAM) and computer data storage. It also encompasses input and output devices like a monitor, mouse and keyboard.

While today’s components are better labeled and cheaper than ever before, the basic makeup of a computer is unchanged.


The processor (also known as the central processing unit, or CPU) acts like the brain of your computer, telling all other hardware components what to do. It interprets instructions sent from an operating system or software application and performs trillions of calculations in order to produce the results that you see on your screen.

The CPU contains a control unit, an arithmetic logic unit and registers. The control unit fetches and decodes the instructions from memory, while the ALU performs arithmetical and logical operations on data. The registers supply operands to the ALU and store the results of those operations. The CPU also contains a cache, which saves time by allowing the CPU to quickly access stored data.


The motherboard is the bridge that allows different parts of your computer to communicate and interact with each other safely and efficiently. It contains a socket for the CPU, RAM slots and expansion slots that allow you to add things like graphics cards or sound cards. It also has power connectors that enable it to receive electrical power from the PSU.

The motherboard also has a chip called the BIOS (Basic Input/Output System) or UEFI (Unified Extensible Firmware Interface), which acts as a firmware that initializes hardware during startup and lets you adjust computer settings. It also acts as the hub for all of your storage devices and external ports.


All the information your processor needs to run your apps and programs is stored in RAM. It offers lightning-fast data access.

The computer system pulls the data out of storage and puts it into RAM for processing, because the hard drive is a lot slower than RAM. If it didn’t do this, your computer would constantly rely on the slow hard drive to find data and would be unresponsive.

The memory consists of capacitors that charge and discharge to store a ‘1’ or ‘0.’ The on-chip SPD (serial presence detect) chip stores the memory’s size, type and speed and provides the system with this information during boot up.

Hard Drives

All data stored on the hard drive comes in the form of binary code – a series of ones and zeros. A read/write head on an actuator arm inputs these codes by magnetizing portions of a disk platter with different electrical charges. The CPU tells the head where to move and which bits of the platter to magnetize.

Each platter has a number of concentric circles divided into logical units called sectors. Each track carries a specific sector number.

Each HDD has shock sensors, such as accelerometers and piezoelectric sensors, which sense mechanical stress on the drive. Significant shocks trigger protective actions to reduce the risk of irreparable damage and data loss.

Graphics Card

The graphics card, or video card, creates the images that are displayed on your computer monitor. Its job is to convert data from the processor into a format that can be interpreted by the monitor.

It’s a powerful specialized processor that crunches the numbers necessary to render real-time 3D images. It stores this information in a pool of Video Random Access Memory (VRAM). The capacity and speed of VRAM directly impact gaming performance. It also performs various display functions and decodes videos. Integrated graphics cards are built into the motherboard, while discrete cards are separate. Both types require their own power source.

Sound Card

The sound card is the hardware that handles all the audio processing. At its most basic it has a digital signal processor that takes some of the load off the central processing unit, a digital to analogue converter and input and output connections for a microphone and speakers.

Some cards will also have a USB connection for digital recording devices. Most cards have their own memory so data representing audio signals can be processed more quickly than on the CPU. They can also provide a variety of other functions and bundled software. There are internal and external cards, the latter being used for laptop computers that do not have room for a full-sized card.