Building or Upgrading Systems - Upgrading and Repairing PCs - page 947

user reviews are also useful in determining product reliability and ease of installation.
Motherboard
Several compatible form factors are used for motherboards. The form factor refers to the physical
dimensions and size of the board and dictates into which type of case the board will fit.
In general, you are safest sticking with the ATX or microATX form factors, as those are the most
popular, and with that you will have the widest choices in cases, motherboards, and power supplies.
Note
For more information on all the motherboard form factors, refer to Chapter 4 . You can also
find the reference standard documents detailing the modern form factors at the Desktop Form
Factors website ( www.formfactors.org ) .
In addition to processor support and form factor, you should consider several other features when
selecting a motherboard. The following sections examine each feature.
Chipsets
Aside from the processor, the main component on a motherboard is called the chipset . This usually is
a set of one or two chips that contain the main motherboard circuits. Where two chips are used, the
chip that connects to the processor is typically known as the PCH (Platform Controller Hub); the
chipset is typically known by the name of the PCH. The PCH supports PCIe x16 slots. The South
Bridge (SB) or I/O controller hub (ICH) chip supports PCIe x1 or x4 slots, USB ports, network ports,
SATA ports, and other types of lower-speed I/O ports.
Note
Older chipsets made for processors that do not include memory controllers used North Bridge
or Memory Controller Hub (MCH) chips in place of the PCH chip.
The chips in the chipset replace the 150 or more distinct components that were used in the original
IBM AT systems and enable a motherboard designer to easily create a functional system from just a
few parts. The chipset contains most of the motherboard circuitry except the processor and memory in
most systems.
Because the chipset really is the motherboard, the chipset used in a given motherboard has a profound
effect on the performance of the board. It dictates all the performance parameters and limitations of
the board, such as memory size and speed, processor types and speeds, supported buses and their
speeds, and more.
Because chipsets are constantly being introduced and improved over time, I can't list all of them and
their functions here; however, you will find a detailed description of many of them in Chapter 4 .
Several popular high-performance chipsets are on the market today.
See the Chapter 4 section, “ Chipsets , ” p. 181 .
See the Chapter 4 section, “ Motherboard Selection Criteria (Knowing What to Look For) , ” p.
260 .