ATX and BTX motherboards are built slightly differently, with the slots positioned in different areas, and the distance between the motherboard and the PC chassis increased in the BTX. In terms of layout, the BTX motherboard mirrors the ATX motherboard. The BTX provides space for installation on the left with empty spaces for cables on the right, and the ATX is laid out vice versa.
In 2004, Intel announced the development of the BTX motherboard, intended to replace the ATX standard of the time. The BTX promised improved internal ventilation to counter higher clock speeds and more components that generated more heat. The introduction of the BTX motherboard was an attempt to standardize the formats of small motherboards.
Because of the layout and the structural differences between the BTX and ATX motherboards, they cannot be installed in interchangeable cases. Also, the BTX motherboard uses PCI Express slots with a 24-pin plug, while the ATX uses a 20-pin plug.
The ATX launched in 1995, but it took two years to become the standard. The BTX failed to achieve similar retail success, in part due to a lack of user interest in the improved cooling system. However, Dell and Gateway both released BTX products.