FlexATX

FlexATX is a motherboard form factor in the ATX family that was introduced by Intel in 1999 as a smaller alternative to the standard ATX design. It was intended to enable compact desktop systems while retaining compatibility with many ATX components and mounting conventions.

Physically, FlexATX boards are smaller than full-size ATX boards. Typical dimensions are around 9 by 7 inches (approximately 230 by 180 millimeters), which allows them to fit in smaller cases and use power supplies compatible with ATX-derived boards. The design preserves the general ATX mounting hole pattern and rear I/O alignment, but the reduced footprint limits expansion capabilities compared with standard ATX. As a result, FlexATX boards generally provide fewer expansion slots than ATX, commonly two to three PCI slots, making them more suitable for compact desktop builds that do not require extensive add-on hardware.

In terms of power and connectivity, FlexATX boards use the same ATX-era approach to power delivery and I/O as other ATX-family boards. They typically support the same back-panel I/O standards and a compatible power connector scheme, though exact configurations vary by model and generation.

Market and legacy notes indicate that FlexATX never achieved broad mainstream adoption and was largely superseded by the microATX form factor, introduced earlier, and later by smaller standards such as Mini-ITX. By the mid-2000s, FlexATX had largely fallen out of production, remaining in use only in some older systems or in niche OEM applications. Today, it is considered largely obsolete, with most enthusiasts and manufacturers favoring microATX or Mini-ITX for compact builds.