The most compelling reason for porting to 64-bit architecture is to gain a much larger memory address space. Moving to 64-bit addressability dramatically increases the potential memory available to applications. Because AutoCAD requires much of its graphics and model data to be memory-resident, the size of the address space directly affects AutoCAD's model size. The following table compares 32-bit and 64-bit maximum sizes for various memory components.
| Architectural Component | Windows 32-bit | Windows 64-bit |
|---|---|---|
| Virtual memory | 4 gigabytes (GB) | 16 terabytes |
| Paging file size | 64 GB | 512 terabytes |
| Paged pool | 470 megabytes (MB) | 128 GB |
| Non-paged pool | 256 MB | 128 GB |
| System cache | 1 GB | 1 terabyte |
| System Page Table Entry (PTE) | 1.2 GB | 128GB |