According to JTB World , AutoCAD 2012 was specifically noted for having faster startups when running on Windows 7 compared to previous versions.
Even on a 64-bit system, you can make AutoCAD 2012 even "better" by following these expert performance tips from AUGI Forums :
While "AutoCAD 2012 portable windows 7 64 bits better" may seem like a specific technical niche, it refers to a highly optimized workflow for users seeking the stability of an older, lighter version of AutoCAD on a classic 64-bit operating system.