Dinesh,
This is a problem with the JPG format itself. It does not lend itself to reading on demand from disk, so applications typically have to completely uncompress JPG files into memory in order to work with them. Rather than JPG, I would instead suggest generating a GeoTIFF file with JPG-in-TIFF encoding so that you get the compression advantages of JPG but the on-demand reading of TIFF. An even better solution is to use ECW or JPEG2000 if AutoCAD will support them.
Let me know if I can be of further assistance.
Thanks,
Mike
Global Mapper Support
support@globalmapper.com