Computer motherboard is the main printed circuit board (PCB) to which most computer components are connected. It provides connectivity between the computer hardware components for instance the processor (CPU), memory (RAM), hard drive, and video card. The motherboard is also called the System Board, Mainboard, Mobo, Main Circuit Board, Planar Board, Logic Board, and Printed Wired Board (PWB), among other names.
The mainboard is located at the bottom or on the side of the computer chassis, depending on the type of desktop computer. The motherboard contains many printed wires that carry power and data signals between components. It connects directly or indirectly to every part of the PC. The type of motherboard installed in a personal computer significantly affects system speed and future expansion capabilities.
What is a Computer Motherboard Made of?
A motherboard is mainly composed of two materials:
- Layers of fibreglass for insulation.
- Copper wires which form conductive pathways.
Computer Motherboard Components
The motherboard holds all the major components of the computer. These components include:
- The processor (CPU)
- CPU socket
- Main Memory (RAM)
- Memory slot
- Math Co-Processor
- BIOS
- CMOS memory
- CMOS Battery
- Expansion slots
- Cache memory
- CPU Clock
- I/O ports
- Hard disk controllers
- SATA connector
- Super I/O chip
CPU- Central Processing Unit
The microprocessor, also known as the “brain of the computer”, fetches, decodes, and executes program instructions while performing mathematical and logical calculations.
The CPU chip is identified by its processor type and manufacturer, which are typically inscribed on the chip. Examples include Intel 386, Advanced Micro Devices (AMD) 386, Cyrix 486, Pentium MMX, Intel Core 2 Duo, and Intel Core i7, among others. The processor fits into the processor socket.
Processor Socket
A CPU socket or processor socket is a connection that allows a computer processor to be connected to the motherboard. We have various types of processor sockets depending on the CPU being inserted. You can identify the processor socket as socket 1 to Socket 8, LGA 775, Socket A, Socket F, among others.
Main Memory (RAM)
The main memory, Primary Memory, System Memory or Random Access Memory (RAM), refers to physical memory internal to the computer. The word main is used to distinguish it from external mass storage devices such as disk drives. The memory is the working place of a computer. It is a hardware device where data is stored and retrieved with ease. It is volatile meaning it holds data as long as there is power. Once the power goes off or the computer is turned off, all the contents in RAM are lost.
The computer can only manipulate data in the main memory. Therefore, every program you execute and every file you access must be copied from a storage device into the main memory. The amount of main memory on a computer is crucial because it determines how many programs you can execute at once and how much data is readily available to a program.
Types of RAM
There are two broad categories of RAM. These are SRAM and DRAM.
Memory Slot
It is also known as memory socket, or RAM slot. This is the slot or connection point where RAM modules are inserted on the motherboard. There maybe two or four RAM slots depending on the motherboard in use.
Math Coprocessor
The Math coprocessor is a type of microprocessor that is optimized to execute complex mathematical calculations e.g. irrational numbers and arrays. It was an optional add-on for earlier Intel processors such as 8086, 80386 and 80486. This allowed computers to perform mathematical calculations faster. It is also known as a numeric coprocessor or a floating-point coprocessor. Modern computer processors come with an integrated math coprocessor.
The 486DX processor was the first processor to include an in-built math co-processor (inside the CPU). The earlier processors 8088, 8086, 80286, 80386SX & DX, and 486SX had their math co-processors on the motherboard.
BIOS- Basic Input Output System
BIOS is a term that stands for basic input/output system. It consists of low-level software that controls the system hardware and acts as an interface between the operating system and the hardware. BIOS is used by the microprocessor to get the computer started after it is turned on.
All motherboards include a small block of Read Only Memory (ROM), separate from the main system memory, used for loading and running software. On PCs, the BIOS contains the code required to control the keyboard, display screen, disk drives, serial communications, and several other functions.
The system BIOS is a ROM chip on the motherboard that the computer uses during the startup routine (boot process) to check the system and prepare the hardware. The BIOS is stored on a ROM chip because ROM retains information even without power. The downside of using ROM in older computers is that you must replace the chip to update the information. Many modern PCs feature flash BIOS, meaning the BIOS is stored on a flash memory chip, which can be updated if necessary.
The BIOS is typically placed in a ROM chip that comes with the computer (it is often called a ROM BIOS). This ensures that the BIOS will always be available and will not be damaged by disk failures. It also makes it possible for a computer to boot itself. Because RAM is faster than ROM, though, many computer manufacturers design systems so that the BIOS is copied from ROM to RAM each time the computer is booted. This is known as shadowing.
The PC BIOS is fairly standardized, so all PCs are similar at this level (although there are different BIOS versions).
Some BIOS hardware configuration options that can be changed
- Change the Boot Order
- Load BIOS Setup Defaults
- Remove a BIOS Password
- Create a BIOS Password
- Date and Time
- Change Floppy Drive Settings
- Hard Drive Settings
- Change CD/DVD/BD Drive Settings
- View Amount of Memory Installed
- Change the Boot Up NumLock Status
- Enable or Disable the Computer Logo
- Enable or Disable the Quick Power On Self-Test (POST)
Unified Extensible Firmware Interface (UEFI)
This is a specification for a software program that connects a computer’s firmware to its operating system. It is expected to replace BIOS.
UEFI is installed at the time of manufacturing and just like BIOS; it is the first program that runs when a computer is powered on. UEFI checks for the hardware components installed on the computer. It wakes the available devices and hands them over to the operating system. It is programmable and hence developers can add applications and drivers. This makes UEFI function as a lightweight operating system. It is managed by a group of chipset, system, hardware, firmware, and operating system vendors called the UEFI Forum.
Advantages of UEFI
- It comes with a user-friendly, graphical user interface.
- It recognizes large storage drives over two terabytes.
- UEFI can support remote diagnostics and repair of computers, even with no operating system installed.
- You can use the mouse in the interface
- It comes with a secure boot feature
CMOS – Complementary Metal Oxide Semiconductor
Motherboards also include a small separate block of memory made from CMOS RAM chips. Other names of the CMOS are RTC (real-time clock), NVRAM (non-volatile RAM) or CMOS RAM. The CMOS RAM is kept alive by the CMOS battery even when the PC’s power is off. This prevents reconfiguration when the PC is powered on. CMOS devices require very little power to operate.
The CMOS RAM is used to store basic information about the PC’s configuration. For instance;
- Floppy disk and hard disk drive types
- CPU
- RAM size
- Date and time
- Serial and parallel port information
- Plug and Play information
- Power Saving settings
The Other Important data kept in CMOS memory is the time and date, which is updated by a Real Time Clock (RTC).
Cache Memory on Computer Motherboard
It is a small block of high-speed memory (RAM) that enhances PC performance by pre-loading information from the (relatively slow) main memory and passing it to the processor on demand.
Most CPUS have an internal cache (in-built in the processor) which is referred to as Level-I cache memory or primary cache memory. This can be supplemented by external cache memory fitted on the motherboard. This is the Level-2 Cache memory or secondary cache. Even though Level-2 cache is optional, it results in a major improvement in performance.
Expansion Buses Found on Computer Motherboard
An expansion bus is an assortment of wires that allows for computer expansion with the use of an expansion board. Expansion buses give rise to expansion slots. The expansion boards are inserted into an expansion slot on the motherboard or backplane that provides additional features to a computer system. Buses carry signals, such as data; memory addresses, power and control signals from component to component.
Expansion buses enhance the PC’s capabilities by allowing users to add missing features in their computers in the form of adapter cards that are slotted in expansion slots.
The different types of buses include PCI, ISA, EISA I/0 bus.
Expansion Slots
Alternatively referred to as a bus slot or expansion port, an expansion slot is a connection or port located on the motherboard. It is a place where an expansion bus can be inserted.
The Chipset on the Computer Motherboard
A chipset is a group of small circuits that coordinates the flow of data and instructions between the central processing unit (CPU) or microprocessor and external devices. This includes the CPU itself, the main memory, the secondary cache and any devices situated on the buses. The chipset also controls data flow to and from hard disks, and other devices connected to the IDE channels.
Chipset manufacturers include Intel, UMC, SIS, VIA, ALI, OPTI etc. The chipset originally was made up of a large number of electronic chips, hence the name. A chipset generally has two components:
- The NorthBridge (also called the memory controller) is in charge of controlling transfers between the processor and the RAM, which is why it is located physically near the processor. It is sometimes called the GMCH, for Graphic and Memory Controller Hub.
- The SouthBridge (also called the input/output controller or expansion controller) handles communications between peripheral devices. It is also called the ICH (I/O Controller Hub). The term bridge is generally used to designate a component which connects two buses.
CPU Clock on the Computer Motherboard
The CPU clock is an internal timing device that breathes life into the microprocessor by feeding it a constant flow of pulses. For example, a 400 MHz CPU receives 400 million pulses per second from the clock. A 2 GHz CPU gets two billion pulses per second. The clock synchronizes the operation of all parts of the computer and provides the basic timing signal for the CPU. Similarly, in a communications device, a clock may be used to synchronize the data pulses between sender and receiver.
Switches
DIP (Dual In-line Package) switches are small electronic switches located on the circuit board that can be turned on or off like a regular switch. Due to their small size, they are typically flipped with a pointed object such as a screwdriver, bent paperclip, or pen top. Care should be taken when cleaning near DIP switches, as some solvents may damage them. They are commonly used to make or break a connection within a circuit.
Jumper pins
Jumpers are small pins on the board with plastic or metal devices that go over the pins. This device is called a bridge. When the bridge is connected to any two pins via a shorting link, it completes the circuit and a certain configuration has been achieved.
Jumper Bridge
A bridge is a metal connector that closes an electrical circuit. Typically, a jumper consists of a plastic plug that fits over a pair of protruding pins. Jumpers are sometimes used to configure expansion boards. By placing a jumper plug over a different set of pins, you can change a board’s parameters.
3-pin Case Fan Connectors on the Computer Motherboard
These pins connect the case fan also known as the system fan. The system fan is used to bring in cool air and blow out hot air from the system unit. This helps cool the computer motherboard components.
Heat Sink
A heat sink is a device made of an aluminium finned radiator designed to absorb excessive or unwanted heat from electronic components. Two types of heat sinks are found on computer motherboards: active and passive. Passive heat sinks consist solely of aluminium-finned radiator material with no mechanical components. In contrast, active heat sinks use computer power and may include a fan mounted on top..
24-pin ATX power supply connector.
This is where you connect the ATX power supply to the motherboard. The corresponding connector has a small clip on the top that snaps to hold the connector in place. The connector is also keyed to ensure it only connects in one direction.
SATA Connectors on Computer Motherboard
This is the connection point on the computer motherboard for mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the earlier Parallel ATA (PATA) standard to become the predominant interface for storage devices.
Super IO Chip on the Computer Motherboard
This type of controller is an integrated circuit found on the computer motherboard. It manages slower and less prominent input/output devices, such as the floppy disk controller, game port, parallel port, real-time clock, and serial port UART, among others.
Conclusion on Computer Motherboard
Well, those are just some of the computer motherboard components. You will find others not discussed here because we have different types of motherboard designs.