1. In personal computers, a motherboard is the central printed
circuit board (PCB) in many modern computers and holds many
of the crucial components of the system, providing connectors
for other peripherals.

3.  A motherboard, like a backplane, provides the
electrical connections by which the other components
of the system communicate, but unlike a backplane,
it also connects the central processing unit and hosts
other subsystems and devices. A typical desktop
computer has its microprocessor, main memory, and
other essential components connected to 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.

4.  Modern motherboards include, at a minimum:
 sockets (or slots) in which one or more microprocessors may be
installed
 slots into which the system's main memory is to be installed
(typically in the form of DIMM modules containing DRAM chips)
 a chipset which forms an interface between the CPU's front-side
bus, main memory, and peripheral buses
 non-volatile memory chips (usually Flash ROM in modern
motherboards) containing the system's firmware or BIOS
 a clock generator which produces the system clock signal to
synchronize the various components
 slots for expansion cards (these interface to the system via the
buses supported by the chipset)
 power connectors, which receive electrical power from
the computer power supply and distribute it to the
CPU, chipset, main memory, and expansion cards.

5.  Motherboards are generally air cooled with heat sinks often
mounted on larger chips, such as the Northbridge, in modern
motherboards. Insufficient or improper cooling can cause
damage to the internal components of the computer and cause it
to crash. Passive cooling, or a single fan mounted on the power
supply, was sufficient for many desktop computer CPUs until the
late 1990s; since then, most have required CPU fans mounted on
their heat sinks, due to rising clock speeds and power
consumption. Most motherboards have connectors for additional
case fans as well. Newer motherboards have integrated
temperature sensors to detect motherboard and CPU
temperatures, and controllable fan connectors which
the BIOS or operating system can use to regulate fan speed.
Some computers (which typically have high-performance
microprocessors, large amounts of RAM, and high-
performance video cards) use a water-cooling system instead of
many fans.

6.  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. The Central
Processing Unit, memory and peripherals were housed on
individual printed circuit boards which plugged into the
backplate. 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 for3D