Motherboard & Hardware Grade 11
A deeper look at what is inside the system unit — the motherboard, its components, buses, expansion cards, and how data flows between parts.
The Motherboard
The motherboard is a large printed circuit board that connects and provides power to all hardware components. It is the central hub of the computer.
Key Motherboard Components
| Component | Description |
|---|---|
| BIOS chip | Basic Input/Output System — first instructions when PC starts. Stored on ROM. Performs POST. |
| CPU socket (ZIF) | Connects the CPU to the motherboard |
| DIMM slots | RAM slots |
| PCI / PCIe slots | Add expansion cards (GPU, sound card, NIC) |
| SATA ports | Connect internal storage (HDD, SSD) |
| Power connector | Supplies power from PSU to all components |
| RAM (DIMM) | Volatile short-term memory for active programs |
| ROM | Read-Only Memory — stores BIOS firmware permanently |
BIOS Functions
- Performs the POST (Power-On Self-Test) — checks RAM, keyboard, storage
- Identifies and initialises hardware devices
- Locates the bootloader and hands control to the OS
- Provides low-level system settings
Motherboard Buses
A bus is a set of wires that transfers data between components.
| Bus type | Purpose |
|---|---|
| Data bus | Transfers data and instructions between components |
| Address bus | Carries the physical memory address of data |
| Control bus | CPU sends signals to coordinate actions |
| Power bus | Delivers electricity to components |
| Internal bus | Links CPU and main memory |
| External bus | Interface for peripherals (USB, SATA, PCIe) |
Data Flow Between Components
Storage → RAM → CPU: Data is loaded from slow storage into fast RAM, then the CPU fetches from RAM for processing.
RAM → VRAM → GPU: Graphics data is moved from RAM to VRAM so the GPU can render images without burdening the CPU.
Cache Memory
Cache is a very small, very fast memory located close to (or inside) the CPU. It stores frequently used instructions so the CPU does not have to wait for slower RAM.
| Level | Speed | Size |
|---|---|---|
| L1 | Fastest | Smallest (inside each core) |
| L2 | Fast | Larger |
| L3 | Moderate | Largest (shared across cores) |
Modular Design
Motherboards use a modular design — individual components (RAM, CPU, GPU) can be upgraded or replaced without replacing the whole computer.