The Big Form Factor Guide - DTX

The DTX standard was created by AMD, and was seen as something of an answer to Intel's failed BTX standards. We provided a primer on DTX when it was first announced, and so will not reiterate too much of that here. However, there are a few salient facts worth mentioning.

DTX and Mini-DTX are intended for smaller systems, including Small Form Factor systems. DTX is somewhat smaller than microATX, and Mini-DTX is slightly larger than VIA's Mini-ITX. The motivation for these standards probably came from several factors:

  1. Only 2 ATX or microATX motherboards can be made from a single PCB "blank", versus 4 DTX or 6 Mini-DTX
  2. The BTX form factors all place the memory "in line" with or offset from the processor; modern AMD processors all have integrated memory controllers and need the RAM slots to be the same (electrical) distance from the processor socket, which is difficult to do with BTX
  3. A typical Mini-ITX motherboard has only 1 expansion slot, versus 2 for both DTX and Mini-DTX

The fact that Intel controls the ATX and BTX families of standards, while VIA controls the ITX family, was most likely also a consideration.


Illustration of DTX relative to other standards

The base standard, intended to represent the best of all worlds. DTX is smaller than microATX (although in practice many microATX motherboards are smaller than the standard specifies, as a cost-saving measure), but avoids some of the weaknesses of the other, smaller standards.

DTX family motherboards are compatible with ATX and microATX cases. Like the BTX family and most of the ITX family, DTX family motherboards use the exact same power connectors as ATX.

Unlike ATX, DTX's short edge is the edge with expansion slots and integrated I/O.

Maximum slots: 2
Width: 8.0 inches (203 mm)
Depth: 9.6 inches (244 mm)
Mounting holes: 6
Introduced: 2007
Link: DTX standard


Illustration of Mini-DTX relative to other standards

Smaller still than DTX, Mini-DTX is just barely larger than Mini-ITX. Critically, it uses that extra size to accomodate another expansion slot. Because only one dimension of the motherboard is changed to go from DTX to Mini-DTX, Mini-DTX's short edge, like ATX and unlike DTX, is not the one with expansion slots and integrated I/O.

Maximum slots: 2
Width: 8.0 inches (203 mm)
Depth: 6.7 inches (170 mm)
Mounting holes: 4
Introduced: 2007
Link: DTX standard