Mini-STX

Lore & Background

Mini-STX was introduced by Intel in 2015 under the name "Intel 5x5". The form factor measures 147mm by 140mm, which is larger than the square NUC (102x102mm) and Nano-ITX (120x120mm) boards, but notably smaller than the common Mini-ITX (170x170mm). Unlike those square standards, Mini-STX is slightly rectangular, being 7mm longer from front-to-rear.

The design suggests (but does not require) support for socketed processors (e.g., LGA or PGA CPUs), onboard power regulation circuitry enabling direct DC power input, and IO ports embedded on the front and rear of the motherboard—similar to NUC but unlike typical motherboards that use headers for enclosure ports.

Adoption by consumer-PC manufacturers remains limited, though ASRock offers DeskMini kits and standalone motherboards, Asus offers VivoMini kits and standalone boards, and Gigabyte offers a few motherboards. Industrial PC suppliers such as Kontron, Iesy, and ASRock Industrial also provide some options.

Reader's Guide

Mini-STX occupies a niche between ultra-compact NUCs and the more common Mini-ITX form factor. Its rectangular shape and suggested design elements—socketed processors, onboard DC power regulation, and front/rear IO ports—aim to enable fully upgradable small-form-factor PCs. However, adoption has been limited among consumer-PC manufacturers, with only a few companies like ASRock, Asus, and Gigabyte offering products. Industrial PC suppliers have also adopted the standard. A derivative called micro-STX, developed by ASRock, adds an MXM slot for PCI Express expansion cards (including graphics or machine learning accelerators) but increases board width to 147 x 188 mm. Overall, Mini-STX remains a relatively uncommon form factor, primarily used in specialized small-form-factor kits and industrial applications.

Did You Know?

• Mini-STX was originally called "Intel 5x5" when released in 2015.
• It measures 147mm by 140mm, making it rectangular rather than square.
• ASRock developed a derivative called micro-STX, which adds an MXM slot and measures 147 x 188 mm.
• The form factor suggests support for socketed processors and direct DC power input.