32bit and 64bit

Autodesk AutoCAD Architecture software is the version of Autodesk AutoCAD software specifically for architects. Architectural drafting features enable you to design and document more efficiently, in the familiar AutoCAD environment. Start working in AutoCAD Architecture and experience productivity gains right away, while learning new features at your own pace.

http://www.autodesk.com/products/autodesk-autocad-architecture/overview