Hardware Reference
In-Depth Information
to help make your system as individual as you are.
Case and Power Supply
The case and power supply unit (PSU) are often sold as a unit, although many vendors do sell them
separately. The power supplies included with lower-cost cases are often of lower quality or provide
an inadequate amount of power, so you might want to replace the existing PSU with one of your
choosing. There are a multitude of chassis designs from which to choose, usually dependent on the
motherboard form factor you want to use, the number of drive bays available, and whether the system
is to be placed on a desktop, on the floor under the desk, on a shelf, or in some other location. There
are cases with extra fans for cooling, front panel I/O and audio ports, removable side panels, and
motherboard trays to make installing a motherboard easier, as well as cases that require no tools for
assembly, rack-mounted versions, and more. For most custom-built systems, a mid-tower case
supporting an ATX or microATX form factor motherboard, along with an ATX12V 2.x or EPS12V
form factor PSU, is the best choice. The ATX12V 2.x and EPS12V PSUs will have the 24-pin main
power connector used on the latest boards, while EPS12V PSUs will also have an 8-pin +12V
processor power connector instead of the standard 4-pin version used on the ATX12V units.
The size and shape of a component is called the form factor . The most popular case form factors are
as follows:
• Full-tower
• Mid- or mini-tower
• Desktop
• Low-profile (also called slimline)
These are not official form factors, like those for motherboards and power supplies; however, each
specific case is designed to accept a specific motherboard and power supply form factor. You have
to ensure that the particular case you choose will accept the type of motherboard and power supply
you want to use.
After you settle on a case form factor, you need to choose one that supports the motherboard and
power supply form factors you want to use. The smaller mini-tower or slimline cases often accept
only microATX, FlexATX, or even smaller motherboards, which somewhat limits your choices.
Within the ATX and BTX families, a larger case always accepts the smaller motherboards. For
example, if a case accepts a full-size ATX motherboard, it also accepts microATX and FlexATX
motherboards.
See the Chapter 4 section, “ Motherboard Form Factors ,” p. 155 .
The case you choose is really a matter of personal preference and system location. Most people feel
that the tower systems are roomier and easier to work on, and the full-sized tower cases have a lot of
bays for various storage devices. Tower cases typically have enough bays to hold floppy drives,
multiple hard disk drives, SSDs, optical drives, tape drives, and anything else you might want to
install. However, some of the desktop cases can have as much room as the towers, particularly the
mini- and mid-tower models. In fact, a tower case is sometimes considered a desktop case turned
sideways, or vice versa. Some cases are convertible—that is, they can be used in either a desktop or
tower orientation.
When it comes to the power supply, the most important consideration is how many devices you plan
to install in the system and how much power they require. Chapter 18 , Power Supplies ,” describes
 
 
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