What is Motherboard?Part 3

The processor socket

The processor (also called the microprocessor) is the computer's brain. It runs programs using a set of instructions. The processor is characterised by its frequency, the rate at which it executes instructions. This means that an 800 MHz processor can carry out 800 million operations per second.

The motherboard has a slot (sometimes several, for multi-processor motherboards) into which the processor is inserted, called the processor socket or slot.

• Slot: A rectangular connector into which the processor is mounted vertically.
• Socket: In addition to being the general term, it also refers more specifically to a square-shaped connector with many small connectors into which the processor is directly inserted.

Within these two large families, there are different versions used, depending on the type of processor. Whatever slot or socket is used, it is essential that the processor be inserted gently, so that none of its pins are bent (it has hundreds of them). To make inserting them easier, a concept called ZIF (Zero Insertion Force) has been created. ZIF sockets have a small lever, which, when lifted, allows the processor to be inserted without applying any pressure, and when lowered, it holds the processor in place.

The processor generally includes some sort of foolproof device, in the form of a notched corner or coloured markings, which must be aligned with the corresponding markings on the socket.

Since the processor releases heat, it is necessary to dissipate it, to keep the circuits from melting. This is why it is generally mounted atop a heat sink (sometimes called a cooler or radiator), which is made of a metal which conducts heat well (copper or aluminium) in order to increase the microprocessor's heat transfer surface. The heat sink includes a base in contact with the processor and fins in order to increase the heat transfer surface. A fan generally accompanies the cooler in order to improve air circulation around it and to improve the heat transfer. The unit also includes a fan which vents hot air from the case and let fresh air come in from outside.

RAM connectors

RAM (Random Access Memory) is used to store data while the computer is running; however, its contents are wiped out as soon as the computer is switched off or restarted, as opposed to mass storage devices such as hard drives, which keep information safe even while turned off. This is why RAM is called "volatile."

Why, then, is RAM used at all, when hard drives cost less per byte stored? The answer is that RAM is extremely fast when compared to mass storage devices like hard drives. It has a response time on the order of a few dozen nanoseconds (about 70 for DRAM, 60 for EDO RAM, and 10 for SDRAM; as little as 6 ns for DDR SDRAM) as opposed to a few milliseconds for a hard drive.

RAM comes in the form of modules which plug into motherboard connectors.

Expansion slots

Expansion slots are compartments into which expansion cards can be inserted. These are cards which give the computer new features or increased performance. There are several types of slots:

• ISA slots (Industry Standard Architecture): For inserting ISA slots. The slowest ones are 16-bit.
• VLB slots (Vesa Local Bus): Bus formerly used for installing graphics cards.
• PCI slot (Peripheral Component InterConnect): used for connecting PCI cards, which are much faster than ISA cards and run on 32 bits
• AGP slot (Accelerated Graphic Port): A fast port for a graphics card.
• PCI Express slot (Peripheral Component InterConnect Express): Faster bus architecture than AGP and PCI buses.
• AMR slot (Audio Modem Riser): This type of slot is used for connecting mini-cards to PCs which are buit for it.

 

the input-output connectors.

The motherboard has a certain number of input/output sockets found on the rear panel.

Most motherboards have the following connectors:

• A serial port, for connecting old peripherals;
• A parallel port, mainly for connecting old printers;
• USB ports (1.1, low-speed, or 2.0, high-speed), for connecting more recent peripherals;
• RJ45 connector (called LAN or ethernet port) used for connecting the computer to a network. It corresponds to a network card integrated into the motherboard;
• VGA connector (called SUB-D15), for connecting a monitor. This connector interfaces with the built-in graphics card;
• Audio plugs (Line-In, Line-Out and microphone), for connecting sound speakers or a hi-fi system, as well as a microphone. This connector interfaces with the built-in sound card;