Inside the Computer: The Motherboard

 Introduction

The motherboard is the central circuit board in a computer that connects all major components, allowing them to communicate and function together. It determines hardware compatibility, including the processor (CPU), memory (RAM), expansion cards, storage devices, and peripherals.

Functions of a Motherboard:

✅ Provides power and data pathways between components.
✅ Houses the CPU socket, RAM slots, expansion slots, and storage connectors.
✅ Contains the chipset, which manages communication between the CPU and other components.
✅ Provides ports for external devices (USB, HDMI, Ethernet, audio).
✅ Includes firmware (BIOS/UEFI) that controls the boot process.

This lecture covers:

• Motherboard form factors (sizes and layout)

• Sockets and slots (CPU, RAM, expansion, storage, and power connections)

1. Motherboard Form Factor

The form factor defines the motherboard’s size, shape, and layout, influencing the number of components it can support.

Common Motherboard Form Factors

Form Factor	Size (Approx.)	Number of Expansion Slots	Common Use
ATX (Advanced Technology eXtended)	12" × 9.6" (305mm × 244mm)	7 PCIe slots	Gaming, high-performance workstations.
Micro-ATX (mATX)	9.6" × 9.6" (244mm × 244mm)	4 PCIe slots	Budget desktops, small gaming PCs.
Mini-ITX	6.7" × 6.7" (170mm × 170mm)	1 PCIe slot	Small form-factor (SFF) PCs, HTPCs.
E-ATX (Extended ATX)	12" × 13" (305mm × 330mm)	8+ PCIe slots	Servers, high-end gaming.

🔹 Why Form Factors Matter:

• Determines compatibility with computer cases.

• Affects cooling and airflow.

• Limits the number of expansion slots and RAM slots.

2. CPU Socket

The CPU socket is where the processor is installed on the motherboard. It determines which CPUs are compatible with the motherboard.

Types of CPU Sockets:

• LGA (Land Grid Array): Intel processors. The pins are on the motherboard, and the CPU has flat contact points.

• PGA (Pin Grid Array): AMD processors. The pins are on the CPU, and the socket has holes to receive them.

• BGA (Ball Grid Array): Found in embedded and laptop systems. The CPU is permanently soldered onto the motherboard.

Examples of CPU Sockets:

Socket Type	Compatible CPU Brand	Example CPUs
LGA 1700	Intel	Core i9-12900K, Core i7-12700K
AM4	AMD	Ryzen 5 5600X, Ryzen 7 5800X
AM5	AMD	Ryzen 7000 Series
LGA 1200	Intel	Core i5-10400, Core i9-10900K

🔹 Why CPU Sockets Matter:

• Determines CPU upgrade options.

• Requires compatible cooling solutions.

• Affects motherboard power delivery and performance.

3. RAM Slots (Memory Slots)

RAM slots hold memory modules, which provide fast temporary storage for active programs.

Types of RAM Slots:

• DIMM (Dual Inline Memory Module): Used in desktops.

• SO-DIMM (Small Outline DIMM): Used in laptops.

Common RAM Types:

RAM Type	Common Speed (MHz)	Used In
DDR3	1600 MHz – 2133 MHz	Older desktops/laptops
DDR4	2133 MHz – 3200+ MHz	Most modern PCs
DDR5	4800 MHz – 6000+ MHz	High-performance PCs

🔹 Why RAM Slots Matter:

• More slots allow for greater memory capacity.

• Dual/quad-channel configurations improve performance.

• Higher-speed RAM enhances system responsiveness.

4. Expansion Slots

Expansion slots allow users to install additional hardware such as graphics cards (GPUs), sound cards, and network adapters.

Types of Expansion Slots:

Slot Type	Use Case
PCIe (Peripheral Component Interconnect Express)	GPUs, NVMe SSDs, Wi-Fi cards.
PCI (Older Standard)	Legacy sound cards, network adapters.

PCIe Versions and Lanes:

PCIe Slot Type	Lanes	Common Usage
PCIe x1	1	Network cards, sound cards.
PCIe x4	4	NVMe SSDs, RAID controllers.
PCIe x8	8	Some GPUs, high-speed adapters.
PCIe x16	16	Graphics cards (GPUs).

🔹 Why Expansion Slots Matter:

• More slots mean more upgrade options.

• PCIe speed affects performance of GPUs and SSDs.

• Future-proofing allows easy hardware upgrades.

5. Storage Slots & Connectors

Motherboards provide slots and connectors for storage devices like HDDs, SSDs, and NVMe drives.

Types of Storage Interfaces:

Storage Interface	Description	Common Use
SATA (Serial ATA)	Used for traditional HDDs and SATA SSDs.	General storage.
M.2	Supports NVMe (fastest) or SATA SSDs.	High-speed storage.
NVMe (Non-Volatile Memory Express)	Uses PCIe lanes for ultra-fast SSD performance.	Gaming, professional workloads.

🔹 Why Storage Slots Matter:

• M.2 slots provide faster data transfer for NVMe SSDs.

• More SATA ports allow for larger storage capacity.

• RAID configurations enhance data security and performance.

6. Power Connections

Motherboards require power connectors to distribute electricity from the power supply unit (PSU).

Common Power Connectors:

Connector Type	Purpose
24-pin ATX Power	Powers the motherboard.
8-pin EPS (CPU Power)	Powers the processor.
PCIe Power (6/8-pin)	Powers dedicated graphics cards.

🔹 Why Power Connectors Matter:

• Insufficient power leads to system instability.

• High-end CPUs and GPUs require additional power connectors.

• Efficient power delivery affects performance and longevity.