Every computer — whether a phone, laptop, or desktop — is built from the same core components. Tap any part below to learn what it does, what types exist, and why it matters.
Remember: All these components communicate through the motherboard — the large circuit board they all plug into. Every signal, every byte of data, every volt of power travels through it. That's why we give it its own dedicated chapter next.
Page 2 — Special Focus
The Motherboard
The motherboard is the backbone of every computer. It is a large printed circuit board (PCB) covered in connectors, chips, and copper traces — the "roads" that data travels on. Every other component plugs into it. Click any part of the diagram to learn what it does.
Interactive diagram — click any component
Click any highlighted component on the board above to learn what it does...
All motherboard components — click to highlight
The motherboard's four main jobs
1 · Physical Home
Holds everything
Provides physical mounting for CPU, RAM, GPU, storage, coolers, and the case itself.
2 · Power Distribution
Feeds electricity
Takes power from PSU and distributes precise voltages to every component through dedicated power planes.
3 · Communication Buses
Moves data
PCIe, SATA, USB, I²C — copper traces carry signals between all components at high speed.
4 · Firmware / BIOS
Starts everything
The BIOS chip stores the code that runs when you press power — it initialises all hardware before the OS loads.
Data highways — PCIe bus
The PCIe (PCI Express) bus is the main highway on the motherboard. It connects the CPU directly to the GPU, NVMe SSDs, and other fast devices. Each PCIe "lane" is a pair of wires — one for sending, one for receiving. More lanes = wider highway = more data per second.
PCIe x1
~4 GB/s
1 lane — Wi-Fi cards, sound cards
PCIe x4
~16 GB/s
4 lanes — NVMe SSDs (M.2 slot)
PCIe x16
~64 GB/s
16 lanes — Graphics cards (GPU)
Fun fact: PCIe 5.0 x16 (the latest standard) can move 128 GB per second between the CPU and GPU — that's 128,000 photographs every second.
Motherboard sizes (form factors)
Form Factor
Size
PCIe Slots
RAM Slots
Best for
ATX
30.5 × 24.4 cm
5–7
4
Full desktop towers, maximum expandability
Micro-ATX
24.4 × 24.4 cm
3–4
4
Compact desktops, good balance
Mini-ITX
17 × 17 cm
1
2
Tiny builds, HTPCs, LAN party rigs
E-ATX
30.5 × 33 cm
7+
8
Workstations, servers, extreme overclocking
Mobile (laptop)
Custom per model
0 (soldered)
0 (soldered)
Thin, portable — not user-upgradeable
Page 3
How they interact
No component works alone. Every task — opening an app, saving a file, playing a game — involves multiple parts passing data between each other at incredible speed. Pick a scenario to see the full journey.
The big picture — who talks to whom
The CPU is at the centre of everything. It talks directly to RAM and the GPU at very high speed. Everything else (storage, USB, audio, network) goes through the chipset on the motherboard.
Central🧠 CPUProcesses everything
⇄
Fast Memory⚡ RAM~60 ns access
⇄
PCIe x16🎮 GPURenders pixels
→
Output🖥️ MonitorHDMI/DP
↕ via Chipset (PCH)
PCIe x4 / M.2💾 StorageSSD / HDD
+
USB / Headers⌨️ I/OKeyboard, mouse
+
Ethernet🌐 NetworkInternet
+
Codec🎵 AudioSpeakers/mic
Speed perspective: The CPU and RAM exchange data in 60 nanoseconds (0.000000060 seconds). In that same time, light travels only 18 metres. Computers operate at a speed that is genuinely difficult for humans to comprehend.
Page 4
Quick Reference
Everything on one page. Use this as a cheat-sheet — all components, their role, typical specs, and how they connect.
Component
Category
Main Function
Connects via
Typical spec
🧠 CPU
Processing
Runs all instructions and calculations
CPU Socket (soldered to board)
4–16 cores, 3–6 GHz
⚡ RAM
Memory
Fast temporary workspace for running apps
DIMM slots on motherboard
8–64 GB, DDR4/DDR5
🎮 GPU
Processing
Renders graphics, pixels, and AI tasks
PCIe x16 slot
4–24 GB VRAM
💾 Storage (SSD)
Storage
Permanently stores files and OS
M.2 slot (NVMe) or SATA port
512 GB–4 TB, up to 7 GB/s
🔧 Motherboard
Main Board
Connects and powers all components
Is the board — everything plugs in
ATX, mATX, Mini-ITX
🔌 PSU
Power
Converts AC mains to DC for all components
24-pin + CPU 8-pin connectors
450 W–1000 W
❄️ Cooling
Thermal
Removes heat from CPU and GPU
Mounts on CPU; fans via 4-pin headers
Air / AIO liquid
🖥️ Monitor
Output
Displays the image rendered by the GPU
HDMI or DisplayPort from GPU
1080p–4K, 60–360 Hz
⌨️ Keyboard / Mouse
Input
Sends commands from user to CPU
USB (wired) or Bluetooth (wireless)
USB 2.0 / 3.2
🌐 Network Card
Connectivity
Connects computer to the internet
Built into motherboard (PCH)
1 Gbps / 2.5 Gbps
Storage speed comparison
Type
Interface
Read Speed
Use case
HDD
SATA
~120 MB/s
Bulk storage, backups
SATA SSD
SATA III
~550 MB/s
Upgrade from HDD — much faster boot
NVMe SSD (PCIe 3)
M.2 / PCIe 3
~3,500 MB/s
Primary drive for OS and games
NVMe SSD (PCIe 4)
M.2 / PCIe 4
~7,000 MB/s
High-end builds, video editing
RAM (for comparison)
DIMM
~50,000 MB/s
Volatile — not storage, but shows the gap
The memory hierarchy — speed vs capacity
As you move closer to the CPU, memory gets faster — and much more expensive per GB, so there's less of it.
L1 Cache
32–64 KB · <1 ns · Inside CPU core · Fastest of all
L2 Cache
256 KB–1 MB · ~5 ns · Inside CPU chip
L3 Cache
8–32 MB · ~30 ns · Shared across all cores
RAM
8–64 GB · ~60 ns · External chips on motherboard
NVMe SSD
256 GB–4 TB · ~100 µs · PCIe on motherboard
Key insight: A CPU's L1 cache is ~100,000× faster than an NVMe SSD but holds ~100,000× less data. The whole hierarchy exists to balance speed and capacity at each level.
Key vocabulary
Transistor
The fundamental building block of all chips — a microscopic electronic switch. Billions per chip.
PCIe Lane
One pair of copper traces carrying data — like a single lane on a motorway. More lanes = more bandwidth.
Clock Speed (GHz)
How many cycles the CPU runs per second. 4 GHz = 4 billion cycles/sec. More GHz = faster (roughly).
Bottleneck
When one slow component limits the speed of faster ones. E.g. a weak CPU "bottlenecking" a powerful GPU.
Bandwidth
How much data can be transferred per second — like the width of a pipe. Measured in GB/s or MB/s.
Latency
The delay before data starts arriving — like how long before a tap gives water. Measured in ns, µs, or ms.
Thermal Throttling
When a CPU or GPU automatically slows down to avoid overheating. A sign of poor cooling.
Form Factor
The physical size and shape standard of a component — e.g. ATX motherboard, 3.5" HDD, M.2 SSD.