The smaller microATX format was also introduced alongside the ATX standard. It was created as a reaction to the changing markets and PC technologies and was compatible with ATX. Compared to a “fully grown” ATX board, which is quite large at 305 mm x 233 mm, microATX boards are much more petite at 244mm x 244 mm. This small size was made possible by limiting the number of PCI/PCIe/ISA/AGP expansion slots on a microATX board to a maximum of four, where full-size ATX products offer up to six. The lower manufacturing costs also made these boards more attractive to a much wider audience. microATX boards are primarily found in computers sold via large distributors and discounters. Conventional office PCs made by the top-tier manufacturers also tend to come equipped with microATX boards.

Another, even smaller form factor was also specified and became known as FlexATX. Again, it uses the same basic elements as ATX and microATX but assembles all of its components on an even smaller area. Like miniITX, FlexATX is especially suited for industrial computers. A downside of the shrunken design is that most components are no longer exchangeable or upgradeable, since there is not enough space for an expansion slot or a processor socket. Instead, the parts are soldered right onto the PCB.

Intel is not the only company to have successfully established a standard. VIA created the miniITX form factor, for example, which is designed for miniature PCs. With boards measuring only 17 cm x 17 cm, these boards are even smaller than those of embedded ITX systems commonly found in industrial environments. These computers use a combination of mobile parts and components that have been soldered on to the PCB, the RAM being the only exception. PCs based on the miniITX standard are so small that they can even use an external power brick instead of a conventional power supply.

miniITX is not only found in normal computers, though. It is also ideally suited for set-top boxes, personal video recorders or similar computer-based devices. This tiny form factor is also a good choice for feature-rich NAS systems. VIA itself utilizes this standard for its Eden platform, which is based on the company’s own C7 processor. While these certainly aren’t at the bleeding edge of performance, they consume very little power, which can be more important, depending on the application.