: Modern CAD files are massive and require more memory to handle 3D rendering and large datasets.
If you are currently using a 32-bit version of an older AutoCAD release, you can continue to use it, but you cannot upgrade to AutoCAD 2020 or newer without a 64-bit OS and hardware [14]. Working with Text in AutoCAD 2020
A: 64-bit is significantly faster for any operation involving large data sets (pan, zoom, regen) because it can cache more in RAM.