Even though a portable version is meant to be lightweight, it still relies on the host machine's hardware to perform. According to official specifications , the 2012 version requires:
AutoCAD 2012 Portable is a self-contained version of AutoCAD 2012 that can be run from a portable device, such as a USB drive or external hard drive. This version of the software is designed to be lightweight and compact, making it easy to carry and use on multiple computers without the need for installation. autocad 2012 portable
AutoCAD 2012 uses the DWG 2010 file format. While it can open older files, it cannot natively open files saved in newer formats (AutoCAD 2013 and newer use the 2013 format, and modern versions use newer formats still). You will need to ask collaborators to "Save As" an older version for you, which disrupts workflows. Even though a portable version is meant to