|Mini-ITX is a
17×17 cm (or 6.7×6.7 inches) low-power motherboard form factor. They
are commonly used in small form factor (SFF) computer systems.
Mini-ITX boards can often be passively cooled due to their low power
consumption architecture. The four mounting holes in a Mini-ITX board
line up with four of the holes in ATX-specification motherboards, and
the locations of the back plate and expansion slot are the same
(though one of the holes used was optional in earlier versions of the
ATX spec). Mini-ITX boards can therefore often be used in cases
designed for ATX, micro-ATX and other ATX variants if desired.
The form factor has provision for one
expansion slot, conventionally a standard 33 MHz 5V 32-bit PCI slot.
Many case designs use riser cards and some even have two-slot riser
cards, although the two-slot riser cards are not compatible with all
boards. Some boards based around non-x86 processors have a 3.3V PCI
slot, and the Mini-ITX 2.0 (2008) boards have a PCI-express ×16
slot; these boards are not compatible with the standard PCI riser
cards supplied with cases.
(sometimes referred to as µATX, mATX or uATX) is a standard for
motherboards that was introduced in December 1997. The maximum size of
a MicroATX motherboard is 244 mm × 244 mm (9.6 in × 9.6 in), but
some MicroATX boards can be as small as 171.45 mm × 171.45 mm (6.75
in × 6.75 in). The standard ATX size is 25% longer, at 305 mm × 244
mm (12 in × 9.6 in).
MicroATX was explicitly designed to be
backward-compatible with ATX. The mounting points of MicroATX
motherboards are a subset of those used on full-size ATX boards, and
the I/O panel is identical. Thus, MicroATX motherboards can be used in
full-size ATX cases. Furthermore, most MicroATX motherboards generally
use the same power connectors as ATX motherboards, thus permitting the
use of full-size ATX power supplies with MicroATX boards.
MicroATX boards often use the same
chipsets (Northbridge and Southbridge) as full-size ATX boards,
allowing them to use many of the same components. However, since
MicroATX cases are typically much smaller than ATX cases, they usually
have fewer expansion slots.
Technology eXtended) is a motherboard form factor specification
developed by Intel in 1995 to improve on previous de facto standards
like the AT form factor. The specification defines the key mechanical
dimensions, mounting point, I/O panel, power and connector interfaces
between a computer case, a motherboard, and a power supply. ATX
addressed many of the AT form factors annoyances that had frustrated
system builders. Other standards for smaller boards (including MicroATX,
FlexATX and mini-ITX) usually keep the basic rear layout but reduce
the size of the board and the number of expansion slots.
The official specifications were
released by Intel in 1995, and have been revised numerous times since,
the most recent being version 2.3, released in 2007.
A full-size ATX board is 12 in × 9.6
in (305 mm × 244 mm). This allows many ATX form factor chassis to
accept MicroATX boards as well.