microATX (also known as µATX) form factor is a small motherboard size of 9.6" x 9.6" (244 mm x 244 mm). Compared to full ATX, microATX has reduced the amount of I/O slots but a smaller power supply can be used.

MicroATX towers can be made slightly bigger than an 8-bit NES, but based on a Pentium 4 or Athlon 64 processor rather than a 6502. They can hold the same hardware as full ATX towers; including more than a gigabyte of RAM; a serial or parallel ATA hard drive; a dual-layer DVD burner; PCI, AGP, and PCI Express cards; floppy drives; and media readers. Power supplies typically range smaller than a mid-tower; however, 450W power supply units do exist.

MicroATX towers are a lot smaller than typical ATX towers. This means that although the same standard hardware is supported, it is supported in lower quantities. For example, an ATX motherboard may support 8 USB ports, while a microATX may support only 4. An added expansion card may bring more USB ports, but the power supply may need to be replaced with a larger one. In addition, the case may only hold one or two 3.5" hard drives and one 5.25" optical drive; external USB hard drives or USB entrapments for PATA drives may be necessary, as well as external CD burners for CD to CD copy.

With only four USB slots and room for a video card and three PCI cards, microATX may seem very restrictive. Still, a microATX system may be very complete. Some configurations could include RAID-0 or RAID-1 on SATA hard drives, a PATA dual-layer DVD burner, a high-end video card, a high-end sound card, a TV tuner, and an additional 6 port combination USB/Firewire card. Such a configuration could support a USB or PS/2 keyboard and mouse; a USB printer; a USB camera; a USB scanner; semi-permanent USB hard drives; USB flash drives; firewire connection to a digital video camera for digital video editing; a DVI interface to a TFT LCD monitor; and of course a connection to the cable or satellite television signal and various video game consoles.

Although the configuration above fills all PCI slots and requires a larger power supply to support the extra USB and FireWire ports, it is notable that external expansion options are not as limited as these. A high-end video card and FireWire card alone could be added to the system; and the USB ports could be supplemented with powered USB hubs. A USB PVR/TV Tuner card and a USB sound card could be acquired and connected to individual ports directly, as these devices are high-bandwidth and real-time. The FireWire devices could also be directly connected; while the rest of the USB devices could be easily connected through powered hubs.

The Shuttle company specializes in small form-factor systems, which they market as their "XPC" range. The dimensions of an XPC system are approximately 30 x 20 x 18.5cm (different models vary), and typically have one AGP and one PCI expansion slot. Though smaller, the XPC range uses many of the same components as larger PCs (including processors, memory and graphics cards), so performance can be on a par with PCs that use a more conventional form factor.

External links

• microATX specifications (Adobe PDF file)

Motherboard

MicroATX