
 ^^^^^^^^^^^^^^
Not unreasonable, since the SMARTDRV packaged with DOS 6 is version 4.1.
Make sure that all your drivers (HIMEM, EMM386, SMARTDRV) are being
executed from the DOS directory.

Loss of the cache provided by SMARTDRV could be your problem; if not,
I don't know what might cause the startup delay.  My testbed for DBLSPACE
(which has a *very* minimal amount of data on the disk so that I don't
eat up too much time as I install and uninstall DBLSPACE) boots in 
about 20 seconds from the "Starting MS-DOS" herald to the end of the
AUTOEXEC.BAT execution.  I don't have handy a system with a more
realistic volume of data to time.