Portable versions are unofficial packages created by third parties and are not supported by Autodesk Instability:
On a fresh Windows 7 64-bit machine, installing standard AutoCAD 2012 takes 20-40 minutes (including .NET Framework and C++ redistributables). A portable version launches within seconds after extraction. For temporary work on a public PC, this is undeniably "better."
New tools allow you to quickly create 2D orthographic and projected views directly from 3D models.
According to JTB World , AutoCAD 2012 was specifically noted for having faster startups when running on Windows 7 compared to previous versions.
Maintain relationships between items in an array; changes to one can propagate to all.
While the installed version requires ~2 GB, a portable version requires enough space on your USB or drive for the extracted files plus temporary workspace. Guide to Using AutoCAD 2012 Portable
A “portable” application is designed to run from a USB drive or a folder without formal installation, leaving no registry entries or system files behind. An would claim to offer full CAD functionality on Windows 7 64-bit without installation.