Form Factor is a standardized specification of a motherboard (including its dimensions, supported power supply types, and layout of components).
AT Form Factor
AT (Advanced Technology) Form Factor was originally made by IBM. It became very popular because they allowed people to copy the design without being sued. Many other manufacturers used this design like Dell, Hitachi, and HP.
- Oldest and biggest form factor and popular until Baby AT.
- Capable of using 386 processor.
- 12′ inch size and was difficult to install, service and upgrade.
Baby AT Form Factor
Baby AT Form Factor is a subset of the original AT Form Factor.
- Standard in computer industries and still being used in Pentium class products.
- CPU socket is placed in such a way that it can interfere with longer bus cards.
- Limitation over peripheral card installation.
- I/O ports are connected to pin-outs near the floppy drive which results in jumbling of ribbon cables.
ATX Form Factor
ATX Form Factor made by Intel. Pushed AT Form Factor and low profile form factors out of the market.
ATX form factor used the idea of an I/O Area with a face plate which supports current and future technologies. It has connections for all input and output peripherals.
ATX defined the Motherboard sizes, but also power supply dimensions. It established a new mounting configuration for power supplies. The processor was relocated away from expansion slots to allow full length add-in cards on the Motherboard. One of its most important characteristics is that it allows for air-flow through the chassis and across the processor for improved cooling.
ATX is also currently (circa 2019) the most widely used Motherboard Form Factor in desktop PCs.
ATX Form Factor subsets include:
- Standard ATX (305mm x 244mm)
- Mini ATX (284mm x 208mm)
- Micro ATX (244mm x 244mm)
- Flex ATX (229mm x 191mm)
- Flex ATX (229mm x 191mm)
- WTX (356mm x 425mm)
Mini ATX Form Factor
Mini ATX is the first subset of ATX Form Factor.
- Commonly same as ATX
- Just change in size from ATX= 12″ x 9.6″ to Mini ATX= 11.2″ x 8.2″
Micro ATX Form Factor
Micro ATX is the 2nd subset of the ATX Form Factor, continually reducing the size of the Motherboard and System Unit.
- Supports current and new processor technologies.
- AGP (Accelerated graphics port) to have high performance graphics.
- Smaller in size and less power supply.
Flex ATX Form Factor
Flex ATX is the next generation of ATX after Micro.
- A subset of Micro ATX.
- Gives chance to system developers to create new personal computer design.
- Enhanced flexibility to allow custom case and board design to be manufactured.
- Small motherboard size and supports current processor technology.
LPX and Mini LPX Form Factor
The LPX (Low Profile Extended) and Mini LPX Form Factors are based on design by Western Digital. Low Profile Extended (LPX) and New Low profile eXtended (NLX) are motherboard form factors known for the usage of a riser card (daughterboard) inserted into a slot near the edge of the board.
The main advantage of this type of design is that expansion cards that plug into a riser card on the LPX/NLX motherboard are parallel with the board which saves space and allows for a smaller system case.
- Usually found in desktop pc’s.
- Case are slim-line, low profile case with riser card arrangement for expansion cards.
- Riser card arrangement means expansion boards are parallel rather than perpendicular.
- This make smaller case but limits number of expansion slots to two or three.
- High quality product at low cost but makes difficult to upgrade and repair.
NLX Form Factor
Low Profile Extended (LPX) and New Low profile eXtended (NLX) are motherboard form factors known for the usage of a riser card (daughterboard) inserted into a slot near the edge of the board. The main advantage of this type of design is that expansion cards that plug into a riser card on the LPX/NLX motherboard are parallel with the board which saves space and allows for a smaller system case.
- Supports current and future processor technologies.
- Also supports new AGP and tall memory technology.
- Installing and upgrading the system is easy.
ITX Form Factor
ITX Form Factor was developed by Via Technologies. Unlike AT and ATX, there is no standard ITX form factor. It is simply defined by its subsets which include:
- Mini-ITX (170mm x 170mm)
- Nano-ITX (120mm x 120mm)
- Pico-ITX (100mm x 72mm)
- Mobile-ITX (75mm x 45mm)
Mini-ITX Form Factor
Mini-ITX is a 17 × 17 cm (6.7 × 6.7 in) motherboard, developed by VIA Technologies in 2001. They are commonly used in small-configured computer systems. Originally, they were a niche product, designed for fan-less cooling with a low power consumption architecture, which made them useful for home theater PC systems, where fan noise can detract from the cinema experience. 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 backplate 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 design provides one expansion slot. Earlier motherboards conventionally have a standard 33 MHz 5V 32-bit PCI slot. Many older 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 older ITX cases.
Nano-ITX Form Factor
Nano-ITX is a computer motherboard form factor first proposed by VIA Technologies at CeBIT in March 2003, and implemented in late 2005. Nano-ITX boards measure 12 × 12 cm (4.7 × 4.7 in), and are fully integrated, very low power consumption motherboards with many uses, but targeted at smart digital entertainment devices such as PVRs, set-top boxes, media centers, car PCs, and thin devices.
There are four Nano-ITX motherboard product lines so far, VIA’s EPIA N, EPIA NL, EPIA NX, and the VIA EPIA NR. These boards are available from a wide variety of manufacturers supporting numerous different CPU platforms.
Pico-ITX Form Factor
Pico-ITX is a PC motherboard form factor announced by VIA Technologies in January 2007 and demonstrated later the same year at CeBIT. The formfactor was transferred over to SFF-SIG in 2008. The Pico-ITX form factor specifications call for the board to be 10 × 7.2 cm (3.9 × 2.8 in), which is half the area of Nano-ITX. The processor can be a VIA C7, a VIA Eden V4, a VIA Nano or any other that uses VIA’s NanoBGA2 technology for speeds up to 1.5 GHz, with 128KB L1 & L2 caches. It uses DDR2 400/533 SO-DIMM memory, with support for up to 1GB. Video is supplied via AGP by VIA’s UniChrome Pro II GPU with built-in MPEG-2, 4, and WMV9 decoding acceleration. The BIOS is a 4 or 8 Mbit Award BIOS.
Mobile-ITX Form Factor
Mobile-ITX is the smallest (by 2009) x86 compliant motherboard form factor presented by VIA Technologies in December, 2009. The motherboard size (CPU module) is 60 × 60 mm (2.4 × 2.4 in). There are no computer ports on the CPU module and it is necessary to use an I/O carrier board. The design is intended for medical, transportation and military embedded markets.