A motherboard form factor is a specification for its general shape and size. It helps to prevent incompatibilities between many hardware manufactures. It also determines the types of power supply, supported case, the physical layout and organization of the board, and the placement of mounting holes. Furthermore, if you construct your own computer system, a form factor is much important as it specifies the correct case and components of the computer system. Nowadays, ATX is the most common form factor for desktop computers. There are different types of form factors of the motherboard, which are as follows:
- AT & Baby AT: Before 1997, a very large motherboard was used by IBM computers. Later, with the time, the motherboard size was reduced and released an extended motherboard using AT (Advanced Technology) form factor. In August 1984, IBM introduced the AT motherboard form factor and widely used in the 1980s. The size of AT is 12″ wide x 13.8″ deep, which is rarely used, and its replaced by ATX and Baby AT.
In 1985, Baby AT motherboard was introduced by IBM that is a replacement for the AT motherboard, which is also known as BAT. It was used until the 1990s, with the 286, 386, 486, and Pentium computers. The width of Baby AT is 8.57″ and 13.04″ deep, which is more similar to the original IBM XT motherboard. It was mainly designed for peripheral devices such as a keyboard and mouse.
- ATX: It stands for Advanced Technology eXtended, which was first released by Intel in July 1995. It is a specification that is used to outline the motherboard and dimension to improve standardization. It includes different versions; the version 2.01 was introduced in February 1997, version 2.03 was released in May 2000. In June 2002, version 2.1 was released, and 2.2 was in February 2004. Until mid-1996, ATX boards were not more popular in the market, when they started to replace Baby-AT boards in new systems. The size of Standard ATX or Full-ATX is 12″ wide x 9.6″ deep. There were some improvements in the ATX form factor as well as a single 20-pin connector for power supply, less overlap between the drive bays and motherboard, and integrated I/O Port connectors soldered directly onto the motherboard.
- BTX (Balanced Technology Extended): BTX is a motherboard form factor that was announced for the replacement of the ATX on 17 September 2003. In February 2004, the first version 1.0 of BTX was introduced. The BTX includes features such as a more efficient layout to facilitate cooling, low profile, support for high-mass motherboard components, and a scalable board to accommodate several system sizes. Intel announced to stop the all future development of BTX in September 2006. It was developed to offer advantages like PCI Express, ATA, and USB 2.0.
Furthermore, it uses in-line airflow and allows to switch the places of memory slots and expansion slots. Its main components, such as chipset, graphics controller, and processor, use the same airflow, which decrease the required fans in the system; that’s why unnecessary noise reduces. The industry considers the ATX form factor in terms of standard, although legacy AT systems are mainly still used today. The BTX form factor is incompatible with the design of ATX. Thus, it is not a standard for the industry.
- DTX: In telecommunications, it stands for discontinuous transmission. It is a method that is used to improve the efficiency of two-way wireless voice communication. It acts by momentarily muting or powering-down to a portable wireless telephone where voice input is not detected.
In the computer, it is a form factor for motherboards, which is a variation of ATX specification. AMD developed the DTX in January 2007. It was designed for small form factor computers such as home theater PCs with dimensions of 8 × 9.6 inches. It is an open standard declared by AMD and is lower compatible with ATX form factor cases. Furthermore, the Mini-DTX, a smaller version, was also developed that had 8.0-inches by 6.7-inches dimensions. It uses fewer layers of printed circuit board wiring through which it offers a lower cost of manufacturing. It was expected to use as a standard for small computers such as Shuttle “SFF” design.
- LPX (Low Profile eXtension): It is the most widely used motherboard form factor that was developed by Western Digital in 1987. The size of an LPX motherboard is 9″ wide and 13″ deep, and used in the late 1980s and throughout the 1990s. As compared to other motherboards, it has several placements of the video, serial, parallel, and PS/2 ports. It is known as low profile as it contains a big slot for a riser card that gives the permission to the expansion cards to be installed parallel to the motherboard. The computers using low profile motherboards are much slimmer as compared to use a Baby-AT motherboard computer.
- microATX: It is a smaller motherboard that is designed by following the ATX form factor, having the same benefits. But it improved the overall design cost by reducing the physical size of the motherboard. In December 1997, Intel developed the first mATX motherboard. The size of mATX is 9.6″ wide x 9.6″ deep, which can be reduced to size as 6.75″ wide x 6.75″ deep. Furthermore, it can also be used in ATX or smaller computer case. It provides more I/O space at the rear, and with the help of integrated Input/Output, connectors help to reduce the emissions.
- NLX: It is based on the boards, stands for New Low Profile Extended. In the late 1990s, the NLX motherboard came to the market. In March 1997, it was developed and finalized by Intel. These motherboards can be removed easily, and it was developed to replace the nonstandard LPX design. The size of the NLX motherboard is 9″ wide x 13.6″ deep maximum to 8″ x 10″ deep minimum. It includes various features such as provide support for AGP, DIMM, USB, Pentium II, larger memory modules, lower cases, and can reduce cable length. Additionally, it is an actual standard (unlike NLX form factor) that has more component options for repairing and upgrading.