Limitations and Restrictions in the 64-bit Environment

In 32-bit Windows, DWG size is constrained both by the 32-bit 2GB virtual memory limit and by internal AutoCAD limitations. 64-bit Windows removes the virtual memory limitation, but AutoCAD does not change the DWG format. To maintain backward compatibility, AutoCAD 64-bit observes the logical limits imposed by the AutoCAD DWG format. For example, the number of symbol table records in a DWG database remains limited to 32K, and xdata still enforces its 16KB per-application limit.