The primary component of a computer is the motherboard (sometimes called the "mainboard"). The motherboard is the hub which is used to connect all of the computer's essential components.
The motherboard has a certain number of input/output sockets found on the rear panel.
Most motherboards have the following connectors:
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:
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.
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.
The real time clock (or RTC for short) is a circuit which synchronises system signals. It is made from a crystal which, as it vibrates, gives off pulses (called timer ticks) in order to keep the system elements running on the same time. The timer frequency (expressed in MHz) the number of times the crystal vibrates each second, i.e. the number of timer ticks per second. The higher the frequency, the more information the system can process.
When the computer is turned off, the power supply stops providing electricity to the motherboard. When the computer is turned on again, the system is still on the right time. An electronic circuit, called the CMOS (Complementary Metal-Oxyde Semiconductor, sometimes called the BIOS CMOS), saves some system information, such as the time, the system date, and a few essential system settings.
The CMOS is kept powered by a battery (a button battery), or a battery located on the motherboard. Information on the hardware installed in the computer (such as the number of tracks or sectors on each hard drive) are stored in the CMOS. As the CMOS is a form of slow storage, certain systems sometimes recopy the CMOS's content into the RAM (fast storage); the term "memory shadow" is used to describe this process of copying the data into RAM.
The "complementary metal-oxide semiconductor" is a transistor manufacturing technology, the latest in a long line which includes the TTL ("Transistor-transistor-logic"), the TTLS (TTL Schottky) (faster), or the NMOS (negative channel) and PMOS (positive channel).
The CMOS allows many complementary channels to run on a single chip. Compared with TTL or TTLS, CMOS is much slower, but it consumes far less energy, which is why it is used in computer clocks, which run on batteries. The term CMOS is sometimes incorrectly used to refer to computer clocks.
The motherboard includes some on-board components, meaning that they are integrated into its printed circuitry:
What's more, recent motherboards generally include a number of onboard multimedia and networking devices which can be disabled:
The motherboard includes some on-board components, meaning that they are integrated into its printed circuitry:
What's more, recent motherboards generally include a number of onboard multimedia and networking devices which can be disabled:
The term "form factor" is normally used to refer to the motherboard's geometry, dimensions, arrangement, and electrical requirements. In order to build motherboards which can be used in different brands of cases, a few standards have been developed:
On most PCs, it is possible to add memory chips directly to the motherboard. You may also be able to upgrade to a faster PC by replacing the CPU chip. To add additional core features, you may need to replace the motherboard entirely.
Taipei, Taiwan, January 4, 2010 - GIGABYTE TECHNOLOGY Co., Ltd, a leading manufacturer of motherboards, graphics cards and other computing hardware solutions today proudly announced that the GA-P55A-UD3 motherboard is the world’s first motherboard to pass USB-IF (Universal Serial Bus-Implementers Forum) certification. As the first motherboard to receive such certification, the GIGABYTE GA-P55A-UD3 is qualified to display the SuperSpeed USB logo, assuring customers their motherboard provides all the speed and power efficiency enhancements that SuperSpeed USB offers, including up to 10x data transfer speed boost over USB 2.0 as well as compatibility with existing USB 2.0 products.
In order to receive certification, the GIGABYTE GA-P55A-UD3 underwent strict compliance and product quality testing from the USB-IF. Other GIGABYTE motherboard models with onboard USB 3.0 are currently being tested and are expected to pass certification within the next couple of weeks.
Motherboards are produced in a variety of sizes and shapes called computer form factor, some of which are specific to individual computer manufacturers. However, the motherboards used in IBM-compatible commodity computers have been standardized to fit various case sizes. As of 2007[update], most desktop computer motherboards use one of these standard form factors—even those found in Macintosh and Sun computers, which have not traditionally been built from commodity components. The current desktop PC form factor of choice is ATX. A case's, motherboard's and PSU's form factor must all match, though some smaller form factor motherboards of the same family will fit larger cases. For example, an ATX case will usually accommodate a microATX motherboard.
Laptop computers generally use highly integrated, miniaturized and customized motherboards. This is one of the reasons that laptop computers are difficult to upgrade and expensive to repair. Often the failure of one laptop component requires the replacement of the entire motherboard, which is usually more expensive than a desktop motherboard due to the large number of integrated components.
A typical motherboard of 2009 will have a different number of connections depending on its standard.
A standard ATX motherboard will typically have 1x PCI-E 16x connection for a graphics card, 2x PCI slots for various expansion cards, and 1x PCI-E 1x (which will eventually supersede PCI). A standard EATX motherboard will have 1x PCI-E 16x connection for a graphics card, and a varying number of PCI and PCI-E 1x slots. It can sometimes also have a PCI-E 4x slot. (This varies between brands and models.)
Some motherboards have 2x PCI-E 16x slots, to allow more than 2 monitors without special hardware, or use a special graphics technology called SLI (for Nvidia) and Crossfire (for ATI). These allow 2 graphics cards to be linked together, to allow better performance in intensive graphical computing tasks, such as gaming and video editing.
As of 2007, virtually all motherboards come with at least 4x USB ports on the rear, with at least 2 connections on the board internally for wiring additional front ports that are built into the computer's case. Ethernet is also included now. This is a standard networking cable for connecting the computer to a network or a modem. A sound chip is always included on the motherboard, to allow sound output without the need for any extra components. This allows computers to be far more multimedia-based than before. Cheaper machines now often have their graphics chip built into the motherboard rather than a separate card.
With the steadily declining costs and size of integrated circuits, it is now possible to include support for many peripherals on the motherboard. By combining many functions on one PCB, the physical size and total cost of the system may be reduced; highly-integrated motherboards are thus especially popular in small form factor and budget computers.
For example, the ECS RS485M-M,[6] a typical modern budget motherboard for computers based on AMD processors, has on-board support for a very large range of peripherals:
Expansion cards to support all of these functions would have cost hundreds of dollars even a decade ago; however, as of April 2007[update] such highly-integrated motherboards are available for as little as $30 in the USA.
Most computer motherboards produced today are designed for IBM-compatible computers, which currently account for around 90% of global PC sale. A motherboard, like a backplane, provides the electrical connections by which the other components of the system communicate, but unlike a backplane, it also hosts the central processing unit, other subsystems, and devices.
Motherboards are also used in many other electronics devices such as mobile phones, stop-watches, clocks, and other small electronic devices.
A typical desktop computer has its microprocessor, main memory, and other essential components on the motherboard. Other components such as external storage, controllers for video display and sound, and peripheral devices may be attached to the motherboard as plug-in cards or via cables, although in modern computers it is increasingly common to integrate some of these peripherals into the motherboard itself.
An important component of a motherboard is the microprocessor's supporting chipset, which provides the supporting interfaces between the CPU and the various buses and external components. This chipset determines, to an extent, the features and capabilities of the motherboard.
Modern motherboards include, at a minimum:
Additionally, nearly all motherboards include logic and connectors to support commonly-used input devices, such as PS/2 connectors for a mouse and keyboard. Early personal computers such as the Apple II or IBM PC included only this minimal peripheral support on the motherboard. Occasionally video interface hardware was also integrated into the motherboard; for example, on the Apple II and rarely on IBM-compatible computers such as the IBM PC Jr. Additional peripherals such as disk controllers and serial ports were provided as expansion cards.
Given the high thermal design power of high-speed computer CPUs and components, modern motherboards nearly always include heat sinks and mounting points for fans to dissipate excess heat.
Prior to the advent of the microprocessor, a computer was usually built in a card-cage case or mainframe with components connected by a backplane consisting of a set of slots themselves connected with wires; in very old designs the wires were discrete connections between card connector pins, but printed circuit boards soon became the standard practice. The Central Processing Unit, memory and peripherals were housed on individual printed circuit boards which plugged into the backplane.
During the late 1980s and 1990s, it became economical to move an increasing number of peripheral functions onto the motherboard (see below). In the late 1980s, motherboards began to include single ICs (called Super I/O chips) capable of supporting a set of low-speed peripherals: keyboard, mouse, floppy disk drive, serial ports, and parallel ports. As of the late 1990s, many personal computer motherboards supported a full range of audio, video, storage, and networking functions without the need for any expansion cards at all; higher-end systems for 3D gaming and computer graphics typically retained only the graphics card as a separate component.
The early pioneers of motherboard manufacturing were Micronics, Mylex, AMI, DTK, Hauppauge, Orchid Technology, Elitegroup, DFI, and a number of Taiwan-based manufacturers.
Popular personal computers such as the Apple II and IBM PC had published schematic diagrams and other documentation which permitted rapid reverse-engineering and third-party replacement motherboards. Usually intended for building new computers compatible with the exemplars, many motherboards offered additional performance or other features and were used to upgrade the manufacturer's original equipment.
The term mainboard is archaically applied to devices with a single board and no additional expansions or capability. In modern terms this would include embedded systems and controlling boards in televisions, washing machines, etc. A motherboard specifically refers to a printed circuit with the capability to add/extend its performance.
