Minimum 4GB (though 8GB+ is recommended for stable performance).
A portable application is one that can run directly from a USB drive or a local folder without the need for a traditional installation process. This usually involves "sequencing" the software into a single executable or a self-contained folder that doesn't modify the host machine's registry or system files. Why Users Look for SolidWorks 2012 Portable Solidworks 2012 Portable