Specifications

CHAPTER 3
156
All About Motherboards
The most popular motherboard form factors are ATX, MicroATX, FlexATX, BTX, and
NLX, in that order.
A motherboard will have one or more Intel sockets for an Intel processor or one or more
AMD sockets for an AMD processor.
Intel, AMD, NVIDIA, and SiS are the most popular chipset manufacturers. The chipset
embedded on the motherboard determines what kind of processor and memory the board
can support.
Two or more video cards installed on a motherboard use NVIDIA SLI or ATI CrossFire
technology.
Buses used on motherboards include conventional PCI, PCI-X, PCI Express, and AGP.
AGP is used solely for video cards. PCI Express has been revised three times and is
expected to replace all the other bus types.
Some components can be built in to the motherboard, in which case they are called
on-board components. Other components can be attached to the system in some other
way, such as on an expansion card.
A bus is a path on the motherboard that carries electrical power, control signals, memory
addresses, and data to different components on the board.
The most common method of configuring components on a motherboard is BIOS
setup. Some motherboards also use jumpers or DIP switches to contain configuration
settings.
Startup BIOS controls the beginning of the boot. It first checks critical hardware
components in a process called POST (power on self test). It then looks to the boot
device priority order stored in CMOS RAM to know which device will be used to
load the OS.
A hard drive has a Master Boot Record (MBR) at the beginning of the drive that
contains the partition table, which contains a map to partitions on the drive.
The next sector on the drive contains the OS boot record. The first file that the OS used
to load the OS is BootMgr for Windows Vista and Ntldr for Windows XP.
Motherboard drivers might need updating to fix a problem with a board component or to
use a new feature provided by the motherboard manufacturer.
Sometimes ROM BIOS programming stored on the firmware chip needs updating or
refreshing. This process is called updating BIOS or flashing BIOS.
When installing a motherboard, first study the motherboard and set jumpers and
DIP switches on the board. Sometimes the processor and cooler are best installed
before installing the motherboard in the case. When the cooling assembly is
heavy and bulky, it is best to install it after the motherboard is securely seated
in the case.
ROM chips contain the programming code to manage POST and the system BIOS and to
change BIOS settings. CMOS RAM holds configuration information.
The BIOS setup program is used to change the settings in CMOS RAM.
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