When we talk about computers and technology, we usually focus on programs, apps, or the operating system, but we leave the other aspects in the background. PTH and SMD components that make it all possibleIf you've ever wondered what's really inside your PC, laptop, or even your mobile phone, you've come to the right place: we're going to calmly dissect what hardware is and how it's organized.
In addition to reviewing the typical list of computer parts, we're going to link that knowledge to more advanced aspects: hardware generations, computer architecture, memory types, buses, peripherals, network hardware, maintenance, and criteria for selecting componentsThe idea is that, whether you're a beginner or already have some experience, you'll finish this article with a very complete overview of hardware components and how they fit together.
What is hardware and how does it differ from software?
In computing, we call hardware everything physical and tangible that forms part of an electronic systemFrom a PC motherboard to a router, a printer, or even a smartphone's microprocessor, these are the parts you can see, touch, and even hear (like fans).
The software, on the other hand, is the logical part: programs, applications, operating system, drivers and dataThe software gives the instructions and the hardware executes them. A common way to explain this is to think of the hardware as the "body" and the software as the "brain"... although, strictly speaking, the real physical "brain" is the CPU.
Without hardware, software would have nowhere to run; without software, hardware would be a pile of inert parts. In any modern computer, we find a combination of main hardware (essential for the equipment to function) and complementary hardware (peripherals and expansions that add extra functions).
Evolution and generations of hardware
Hardware hasn't always been like it is today; it has gone through several generations marked by very clear technological leaps in internal electronicsUnderstanding this evolution helps us understand why we now have such powerful, small, and efficient equipment.
In the so-called first generation (approx. 1940-1956), computers used empty tubesThey were gigantic, slow machines that consumed enormous amounts of energy and generated a great deal of heat. They were mainly used in laboratories, universities, and military projects.
The second generation (1956-1963) replaced the tubes with transistorsComputers became smaller, faster, and more reliable, and the first programming languages and operating systems appeared. The logic remained similar, but the physical implementation changed completely.
With the third generation (starting in 1964) came the integrated circuits or chipswhich allowed many transistors to be integrated onto a single silicon chip. This dramatically increased capacity, reduced costs and size, and laid the foundation for computers as we know them today.
The appearance of microprocessor (like the Intel 4004 in 1971) is often considered by many authors to be the beginning of the fourth generation: a complete CPU integrated onto a single chip. At the same time, very-large-scale integration (VLSI) circuits, with millions of transistors, became popular, opening the door to home PCs, laptops, and later, smartphones.
Today, rather than abrupt leaps, we are experiencing continuous evolution: every few years, integration density, speed, and energy efficiency improve, and technologies such as the Artificial Intelligence, virtual reality, the Internet of Things (IoT) or systems on a single chip (SoC), which integrate CPU, GPU, memory controllers, Wi-Fi, Bluetooth and more into a single circuit.
Computer system architecture: essential building blocks
If we simplify a computer to its most basic functions, we always find the same blocks: input, processing, memory, output, and storageThe classic architecture of computers is built upon this scheme.
In the center is the Central Processing Unit (CPU)The processor executes instructions and performs arithmetic and logical operations. Around it are organized the main memory (RAM), auxiliary memory (HDD disks, SSDs, tapes, etc.), input devices (keyboard, mouse, scanner…), output devices (monitor, printer, speakers), and mixed peripherals (disks, network cards, touch screens…).
Most of the electronic components that bring this system to life are mounted on the motherboard or mainboard, a large printed circuit board that houses the chipset, the processor and RAM sockets, the data buses, the expansion slots, and many integrated connectors and controllers.
In recent years, more and more functionality has been integrated directly into the motherboard or even the processor itself (integrated graphics, memory controllers, connectivity modules). The systems “System on a Chip (SoC)They take this to the extreme, something very common in mobile phones, tablets, IoT devices, and miniPCs such as Khadas VIM2.
Main internal hardware components
Inside the tower (or the chassis of a laptop) we find a series of components without which the computer simply wouldn't start. Let's review the most important hardware components and their role within the system.
motherboard or motherboard
The motherboard is the meeting point of all components. A printed circuit large size where the chipset, CPU and RAM sockets, expansion slots (PCIe, M.2…), SATA connectors, rear ports (USB, HDMI, audio, network, etc.) and internal connectors for fans, front panel, etc. are soldered.
Its key functions are to provide a physical connection, distribute electrical power, manage data communication, time and synchronize signals and monitor certain parameters (temperatures, voltages, fan speeds, etc.). The quality of the chipset and the motherboard design determine the overall performance and expansion possibilities.
On the plate itself we also find serial numbers, labels, and revisions These details allow you to identify the exact model, manufacturing date, or product version. This information is very useful for finding suitable drivers and BIOSes, or for checking compatibility.
Microprocessor or CPU
The microprocessor, or CPU, is the true physical “brain” of the computer: It interprets and executes program instructions, performs calculations, and coordinates the other components.Internally, it consists of two main blocks: the Arithmetic Logic Unit (ALU), which is responsible for operations with binary numbers and logical functions, and the Control Unit, which decides the order in which the instructions are executed and where the data flows at each moment.
Two very important parameters of a CPU are the number of internal bits it works with in parallel (the internal bandwidth: nowadays, virtually all consumer processors are 64-bit) and the clock frequency, measured in Hz, MHz or GHz, which indicates how many cycles per second the processor can perform.
In addition, the CPU communicates with the rest of the system through the data busThe greater its bandwidth (number of bits it can transfer at once) and the higher its frequency, the faster the transfer between the processor, memory, and other devices. In practice, the final performance depends on a combination of all these factors: architecture, frequency, number of cores, cache, and bus speed.
Modern processors are mounted on a specific motherboard socket and require a good cooling system: heat sink and fanAnd in many cases, high-quality thermal paste or even liquid cooling. A modern CPU can consume 40-130 W or more, which is directly converted into heat.
Main memory: RAM
RAM (Random Access Memory) is the CPU working memoryThis is where the operating system and running programs are loaded, as well as the data being worked on at any given time. It is volatile memory: when the computer is turned off, its contents are lost.
Modern RAM is supplied in the form of modules (DIMMs for desktops, SO-DIMMs for laptops) that are inserted into slots on the motherboard. Internally, it is usually DRAM (dynamic) memory, organized in arrays of very simple cells (one transistor and one capacitor per bit), which need to be constantly "refreshed" to retain information.
There are several generations of memory: SDR SDRAM, DDR, DDR2, DDR3, DDR4 and DDR5Each one offers improvements in speed, transfer rate, and energy efficiency. Current DDR memory can transfer data at several gigatransfers per second and operates with enormous bandwidths, which is crucial for properly powering modern CPUs and GPUs.
Besides typical DRAM, there are other types of RAM with specific uses: SRAM (fast, doesn't need refreshing, used in caches), the NVRAM (non-volatile, retains data without power, very common in flash memory, USB drives, etc.) or the VRAM, used in graphics cards to store textures and screen information.
ROM memory, BIOS and motherboard battery
Alongside RAM, there is another fundamental memory: ROM (Read Only Memory), which originally held information read-only data required for system startup and basic configurationToday, a reprogrammable variant known as BIOS or, in more modern versions, UEFI is used.
The BIOS/UEFI is a small program stored on a chip on the motherboard that runs as soon as the computer is turned on. It is responsible for Initialize and test components, detect disks, configure low-level parameters, and hand control over to the operating system.Part of its configuration is saved thanks to a small battery on the board; when that battery runs out, settings such as the date, time, or certain boot parameters are lost.
Cache memory and virtual memory
cache memory is a ultra-high-speed RAM integrated into the processor (and in some cases very close to it) that stores the data and instructions that the CPU uses most frequently. Its purpose is to minimize the time it takes the processor to obtain what it needs, avoiding constant access to RAM, which is considerably slower.
It is usually organized into several levels: L1 cache (very fast and small, per core), L2 cache (somewhat larger and slower) and L3 cache (even larger and shared between cores)The processor first searches the L1 cache, then L2, then L3, and if it doesn't find what it needs, it accesses RAM. The more cache (and the better managed it is) a processor has, the more efficient it will be in many workloads.
On the other hand, virtual memory is an operating system mechanism by which It uses part of the hard drive or SSD as a RAM expansion.When physical memory runs out, the system moves less frequently used data to disk to free up RAM. This allows more programs to be opened, but if virtual memory is overused, performance drops sharply because the disk is much slower than RAM.
Mass storage: HDD hard drives, SSDs, and more
Mass storage is responsible for save data permanently or semi-permanentlyOperating system, programs, documents, photos, videos, backups, etc. Traditionally, this role has been played by the mechanical hard drive (HDD), although nowadays it competes (and in many cases is displaced) by solid state drives (SSD).
A hard disk drive (HDD) stores information on several magnetic platters that spin at high speed (7200 rpm is a typical value today) and are read by highly precise read/write heads. The surface of each platter is organized into tracks, sectors, and clusters; the latter are the smallest units of allocation. Capacity (in GB or TB) and rotation speed These are two key parameters when choosing a hard drive.
SSD drives, on the other hand, use flash memory without mechanical partsThis greatly reduces access time and increases read and write speeds. They are more resistant to shocks and vibrations, but are usually more expensive per gigabyte than an HDD. In practice, it is very common to use an SSD for the operating system and programs and a high-capacity HDD for data.
In professional environments we also find disks SAS or NVMe-based solutions over PCIewith even greater bandwidths. In addition, we can add other storage media to the list: optical drives (CD, DVD, Blu-ray), magnetic tapes for backups, USB flash drives, memory cards, etc.
Fuente de alimentación
The power supply is responsible for transform the alternating current from the grid (230 V in Spain) into stabilized direct current (+3,3V, +5V, +12V, etc.) that the computer components may use. A bad power supply can cause crashes, instability, or even damage the equipment.
When choosing a font, we need to look at the total power (watts), design quality, energy efficiency (80 PLUS and similar) and the number and type of connectors available (for CPU, motherboard, GPU, hard drives, etc.). More powerful systems, with multiple graphics cards or many hard drives, require significantly higher capacity power supplies than a basic office computer.
Chassis and cooling systems
The chassis or box is not just “the wrapping”: it is the structural support where all components are mounted and plays a key role in the system ventilationA larger chassis usually offers more drive bays, more space for expansion cards, and better airflow, as well as making assembly and cable management easier.
To keep everything running at reasonable temperatures, we need good cooling systems: Passive heatsinks (metal blocks with fins), air fans, and, in more demanding systems, closed-loop or custom liquid cooling.Poor ventilation can cause the CPU, GPU, or chipset to overheat, reduce their frequency (throttling), or even shut down to protect themselves.
Graphics card and video hardware
The graphics card, or GPU, is a component specialized in process and generate 2D/3D images, animations and graphicsModern GPUs are true floating-point computing monsters and are used not only for video games, but also for video editing, 3D design, scientific computing, or artificial intelligence (what is known as GPGPU).
There are two main types: integrated solutions (IGP), which are located within the processor or motherboard and use system RAM, and Dedicated graphics cards, with their own VRAM memory and a much more powerful GPUThese latter ones are usually connected via PCI Express slots and are preferred for gaming and graphics-intensive tasks.
Regarding video connections, nowadays we find VGA (now almost obsolete), DVI, HDMI and DisplayPort portsHDMI and DisplayPort are the most common for modern monitors and televisions, allowing high resolutions, high refresh rates, and simultaneous transmission of audio and video.
Ports, buses and controllers
In order for all these components to communicate and for external devices to connect, the computer has Internal buses and entry/exit portsThis is where concepts like PCIe, SATA, USB, Ethernet, etc. come into play.
The PCI expansion slots and, above all, PCI Express They allow you to connect additional cards: graphics cards, sound cards, video capture cards, high-performance network cards, etc. In terms of storage, the old IDE/ATA interfaces have been almost completely replaced by SATA and, in the fastest SSDs, by NVMe over PCIe.
The controllers or interfaces are the circuits that manage the flow of data between the CPU/memory and the various devices (disks, optical drives, external buses…). Previously, many controllers were separate cards; today, most are integrated into the chipset or even the device itself (for example, SCSI, FireWire, or certain RAID controllers). In certain electronic designs, they are used optocouplers to isolate and protect signal lines.
Regarding external physical ports, the most common are the USB (1.x, 2.0, 3.x, USB-C), the RJ45 network port (Ethernet), analog audio ports, HDMI, DisplayPort and, on older equipment, PS/2 for keyboard and mouse, or serial and parallel portsFurthermore, laptops and mobile devices make extensive use of wireless technologies such as Wi-Fi, Bluetooth, or even infrared in its day.
Peripherals: input, output, and mixed devices
Peripherals are the external devices that allow the computer to communicate with the world: receiving information (input), displaying results (output), or both (I/O). While many are considered accessories, others are essential for everyday use.
Input devices
Input devices allow a user or an external system to send data and instructions to the computer. Typical examples include: keyboard and mouseessential in most desktop PCs, but there are many more.
This category would also include scanners, microphones, webcams, barcode readers, joysticks, digitizing tabletsas well as CD, DVD, or Blu-ray drives when used in read-only mode. In industrial environments, it is very common to find data acquisition cards, sensors, and specific control systems.
Output devices
Output devices display or reproduce the results of processing. The most obvious case is the monitorwhich displays the desktop, programs, and everything that happens on the system. Alongside it, the printers and speakers These are the other major output peripherals: they allow us to obtain on paper what we have done or to listen to sounds, music, notifications, etc.
Although they could function without a printer or speakers, most users consider these peripherals almost as basic as the monitor itself, especially in office, education, or entertainment environments.
Mixed peripherals and external storage
Mixed peripherals are those that can function as both input and output devices. The clearest examples are hard drives, SSDs, USB flash drives, memory cards, or magnetic tape drives.which allow reading and writing data about them.
Mixed peripherals are also considered network cards, modems, video capture/output cards, touch screens (which display information and receive touches) or, in general, any device that exchanges information in both directions with the system.
External mass storage devices, such as USB drives or network-attached storage (NAS, SAN) units, play a key role in backups, archiving of large volumes of data, and information mobilityAlthough the system could start without them, in professional environments they are almost indispensable.
Network hardware and connectivity
In a hyper-connected world, it's unthinkable to talk about hardware without mentioning the network hardwareThis component is responsible for enabling devices to communicate with each other and with the internet. It is essential in both businesses and homes.
The basic devices are the routers, switches, Wi-Fi access points, firewalls and network interface cards (NICs)The router directs traffic between the local network and the outside, the switch organizes internal communication between various devices, and the firewall acts as a security barrier against attacks and unauthorized access.
More advanced solutions are used in servers and data centers: Managed switches, high-speed links (10/40/100 GbE), dedicated load balancing hardware, redundant systems and complex configurations to ensure availability, scalability, and security.
Other types of hardware according to their marketing
In addition to being classified by function, hardware is also often differentiated according to how it is marketed and what type of user it is aimed atThis is where terms like OEM, Box, Retail or Refurbished come into play.
El OEM (Original Equipment Manufacturer) hardware This is the type typically sold to manufacturers or equipment assemblers. It usually comes without a fancy box, extras, sometimes without a printed manual or direct support, but in return, it's more economical. It typically arrives already assembled inside a brand-name PC or server.
The call hardware Box This is the version sold to the end user in a complete package, with manuals, discs (or software access), a license where applicable, and often better warranty terms. The price is usually higher than the OEM version of the same product.
When talking about Retail hardware This refers to direct sales to consumers in stores, applying the retail price set by the distributor. And finally, the Refurbished or renewed hardware These are products that have been returned to the manufacturer due to a defect or excess stock, have been checked or repaired, and are put back on sale at a lower price and, usually, with a shorter warranty.
Hardware speed, capacity, and performance
To evaluate and compare hardware components, it is helpful to have a few things clear. basic units of measurementIn storage we use the byte as the fundamental unit and its multiples: KB, MB, GB, TB… Remember that 1 KB in classic computing is 1024 bytes, 1 MB is 1024 KB, and so on.
Data transmission commonly uses bytes per second (B/s, KB/s, MB/s, GB/s) Or, very often, bits per second (b/s, Kbps, Mbps, Gbps), especially in network and internet connections. Keep this in mind, because 1 byte is 8 bits, so 100 Mbps is not the same as 100 MB/s.
The speed of electronic components is often expressed in Hz (hertz), which means times per second that something repeatsA 3 GHz processor performs three billion clock cycles per second; a 533 MHz bus allows its data bandwidth to be transported hundreds of millions of times per second.
The overall speed of a computer depends on several factors combined: RAM capacity and speed, CPU frequency and architecture, bus width and speed, storage type, GPU performanceetc. It's not very useful to install a top-of-the-range processor if it's paired with little slow RAM, an old hard drive, and a very limited graphics card.
Criteria for choosing and assembling hardware components
When we plan to assemble or upgrade a PC, a server, or even a simple office computer, it's important that the components are... balanced with each other and compatibleOtherwise, we could end up with what many call a "Mercedes engine in a 600 body".
For basic office tasks, browsing, and light use, a mid-range/low-end processor will suffice. a decent amount of RAM (e.g., 8-16 GB), an SSD as the main drive, and integrated graphicsHowever, for video editing, gaming, or 3D design, we'll need more powerful CPUs, more memory, a dedicated GPU, and perhaps several fast storage drives.
It's also worth thinking about the future: choosing a motherboard that allows upgrade RAM, change CPU, add more drives or cards and that it has enough USB, SATA, M.2, etc. ports. The power supply should have room for future upgrades, and the chassis should have adequate space and ventilation.
Finally, compatibility must be carefully checked: CPU socket type, supported RAM generation, motherboard physical form factor (ATX, microATX, ITX), graphics card dimensions, required power connectors, etc. Good planning beforehand saves headaches and returns.
Hardware maintenance and care
Even the best hardware in the world will fail if it isn't properly cared for. Basic but consistent maintenance is key. to extend the lifespan of components, prevent failures, and maintain stable performance.
The first thing is to keep the equipment clean: Dust and dirt clog vents, fans, and heat sinksThey raise temperatures and can cause anything from random restarts to serious breakdowns. Periodic passes with compressed air (with the equipment switched off and unplugged) help a lot.
It is also important to monitor the health of the system with tools that Monitor CPU and GPU temperatures, disk status (SMART), voltages, and fan speeds.etc., and consult guides on how to test electronic components when anomalies are detected.
Another key point is to keep the firmware (BIOS/UEFI) and drivers for the main componentsThis improves compatibility, fixes bugs, and sometimes even enhances performance. However, firmware updates must be performed carefully and following the manufacturer's instructions.
When handling internal hardware, it is recommended to download the static electricity (using anti-static wrist straps or touching a grounded metal surface) and work in an orderly fashion: disconnect the equipment, organize the cables properly to avoid pulling and double-check before turning it on.
Ultimately, understanding what each component does and how it relates to the others allows us to make smarter decisions when buying, building, or maintaining a computer, avoid bottlenecks, and get much more out of our hardware without overspending.
