Hardware Reference
In-Depth Information
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
willhavethe24-pinmainpowerconnectorusedonthelatestboards,whileEPS12VPSUs
willalsohavean8-pin+12Vprocessorpowerconnectorinsteadofthestandard4-pinver-
sion 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 sup-
plyformfactor.Youhavetoensurethattheparticularcaseyouchoosewillacceptthetype
of motherboard and power supply you want to use.
After you have settled 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.
WithintheATXandBTXfamilies,alargercasealwaysacceptsthesmallermotherboards.
Forexample,ifacaseacceptsafull-sizeATXmotherboard,italsoacceptsmicroATXand
FlexATX motherboards.
See
“
Motherboard Form Factors
,”
p.
143
(
Chapter 4
, “
Motherboards and Buses
”
).
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
