Back when I built my first PC, computers were enormous because motherboards were enormous. The AT form factor (from 1984) measured 12 x 11–13 inches (305 x 279–330 mm), while the popular ATX design that superseded it in 1996 wasn’t much smaller (12 x 9.6 inches, 305 x 244 mm).
Fast forward to today and PCs have shrunk considerably with the arrival of Mini-ITX and the Intel NUC. Now, slotting between these two designs is a new motherboard option — Mini-STX. Originally introduced by Intel as the 5×5, Mini-STX measures 5.5 x 5.8 inches (140 x 147 mm), which makes it 29% smaller than the 6.7 x 6.7 inch (170 x 170 mm) Mini-ITX.
It’s surprisingly versatile, supporting LGA-based CPUs up to 65W TDP (from Intel Celeron to Intel Core i7 processors), 2x SODIMM slots, 2.5-inch SATA or M.2 storage options, plus wired and wireless networking. While it’s bigger than a 4×4 Next Unit of Computing, Mini-STX gives you something the NUC doesn’t — the freedom to swap out the processor and upgrade it.
This ability to upgrade the processor is arguably the big draw. As ASRock points out, Mini-STX “grants users the freedom of choosing their own six generation processor, as well as a standard desktop CPU fan… Ultimately, it’s less power consuming than the average desktop configuration, it is also way more flexible and powerful than NUCs.”
ASRock was one of several manufacturers showing off Mini-STX solutions at CES 2016. The ASRock H110M-STX board, for example, is based on the Intel H110 chipset and features integrated Intel HD graphics, 2x SODIMM (for DDR4 2133MHz RAM), HDMI, DisplayPort and VGA connectivity, plus four USB 3.0 ports, including one Type-C.
Mini-STX computers are starting to appear too. ASRock has its compact H110M-STX MINI PC, while MSI supports the 5×5 form factor with its Cubi 2 Plus desktops — a PC so small you an attach it to the back of a flatscreen monitor.
It’s easy to see the appeal. As Jared Newman wrote on pcworld.com: “The Cubi 2 Plus, for instance, measures just 6.1 x 5.8 x 2.3 inches. That’s only about an inch and a half longer and deeper than Intel’s larger NUC kits, while a small mini-ITX enclosure can easily be twice as large.”
Ultimately, Mini-STX offers the small form factor advantages of a NUC with the upgradeability of Mini-ITX. It makes 5×5 boards ideal for use in living room entertainment boxes, simple gaming PCs, or as a way of streaming content from a networked gaming system, Steam Link-style.