microATX Motherboard Interface Specification

Version 1.2

Page 10

To avoid damage to traces on microATX and ATX motherboards, chassis standoffs in any locations not

specified for microATX and ATX should be removable or not be implemented at all.

ABC

GH J

New for microATX

9.6” (244 mm)

REAR of board

FRONT of board

NOT TO SCALE

12” (305 mm)

9.6”

(244 mm)

6.25” wide rear

I/O shield

PCI/ISA/AGP

connector

locations (4 max)

Key, mounting holes

ATX

microATX

Form factor Mounting hole locations Notes

microATX B, C, F, H, J, L, M, R, S Holes R and S are added for microATX form factor.

Hole B was defined in Full AT format

ATX A, C, F, G, H, J, K, L, M Hole F must be implemented in all ATX 2.1-compliant chassis

assemblies. It was optional in the ATX 1.1 specification.

Figure 2: microATX and ATX Form-factor Mounting Holes

Notes: In Figure 2, Figure 3, and Figure 8, the board is shown oriented with the rear of the board toward the top.

The shaded portion to the left above indicates the greater width of the ATX form factor.

For details about mounting holes and board sizes, see the mechanical drawing in this specification.