The DTX form factor is a variation of ATX specification designed especially for small form factor PCs (especially for HTPCs) with dimensions of 8 × 9.6 inches (203 × 244 mm). An industry standard intended to enable interchangeability for systems similar to Shuttle's original "SFF" designs, AMD announced its development on January 10, 2007. AMD stated that the DTX form factor is an open standard, and is backward compatible with ATX form factor cases. They also present a shorter variant named Mini-DTX which is smaller in PCB size of 8 × 6.7 inches (203 × 170 mm).
The specification provides for up to 2 expansion slots on a DTX motherboard, in the same position as the top two slots on an ATX or microATX board. Upcoming DTX boards will likely contain one PCI Express slot and one PCI slot. The spec also provides for optional ExpressCard expansion slots on DTX motherboards.
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