Computer hardware consists of the physical components that make up a computer, including central processing units (CPU), random access memory (RAM), hard drives and graphics cards. It also includes external devices like mice and keyboards.
A close-up of the flat motherboard that connects all the other hardware components together. At the center is the CPU, which has a metal cover that presses tightly against the fingernail-sized chip and helps conduct heat to its own large copper “heat sink”.
Motherboard
The motherboard acts as a central hub connecting all of your computer’s functional components so they can communicate with one another. It features slots for the CPU socket, RAM, and expansion cards. It also has connectors for storage devices and power supplies.
The CPU, also known as the central processor unit, takes input from your keyboard and mouse and executes instructions specified by desktop programs to perform tasks. It works with a chipset, a set of specialized integrated circuits that manage the flow of data between the CPU and other components on the motherboard.
The motherboard contains the BIOS, also called UEFI (Unified Extensible Firmware Interface), which stores the firmware responsible for kickstarting the hardware during startup and giving you a dashboard to adjust system settings. It also has a cooling fan that eliminates excess heat to prevent damage.
CPU
The CPU is like the brain of your computer and is essential for carrying out all the complex operations that power modern software applications. It is also responsible for interpreting and processing input from various other devices like your mouse, keyboard, or microphone.
It does this by executing instructions in sequence, millions of times per second. This process is known as the fetch-execute cycle. It starts with a request for an instruction from memory. This is followed by decoding it into its components by a circuit called an instruction decoder.
The data is then fetched from memory and loaded into registers for the next steps in the operation. This saves time compared to having to retrieve the data from memory each time. The CPU also contains cache memory that stores data and instructions for faster access.
RAM
RAM is the super fast, high speed memory that your computer and applications use to store temporary data. It’s how your PC can perform tasks seemingly instantly.
Unlike storage, which stores data in folders on a hard disk or solid state drive, RAM is immediately accessible by your processor. This is why it’s orders of magnitude faster than accessing data on a storage device.
Modern computer systems often use SDRAM or DDR memory. These work by syncing with the system clock. A pulse of the system clock, seen as a sine wave, tells SDRAM or DDR to transmit data. Newer generations of this technology enable more data to be sent during each pulse, boosting performance.
RAM comes in modules that are soldered directly to the motherboard, or in removable sticks called DIMMs that slot into the motherboard. Most desktops allow users to upgrade the amount of RAM up to a limit.
Graphics Card
The graphics card handles the specialized workload involved in rendering images for display on your computer’s screen, including 3D computer games. Before installing a new graphics card, make sure your system’s motherboard has an open expansion slot and that the power supply unit (PSU) provides enough wattage for the card to function.
The graphics card processes binary data sent by the CPU and converts it into pixels, tiny squares of color that combine to form a picture. It then sends this information to the monitor via a cable, such as DVI, HDMI, or DisplayPort. The graphics card requires a separate pool of video memory, called VRAM, in addition to the general RAM that’s used by the computer as a whole. This allows the graphics card to work more quickly than a CPU could by itself.
Hard Drives
The hard drive stores the operating system and applications on a non-volatile, long-term storage medium. Manufacturers have been on a constant quest to decrease physical size and cost while increasing storage capacity since IBM invented the first hard disk drive in 1956.
The microcontroller on the PCB sends a command to the platters, instructing them to save and retrieve data. The PCB also holds components delivering power to the platters at the right time and directing heads to and from the platters, among other things.
All digital data comes in the form of binary code, a series of ones and zeros that represent information. Each platter has thousands of tiny sections that can accept an electric charge, and each head can detect the changes in that surface to interpret the bits as either a 1 or a 0. This is how hard drives store and retrieve data.