Fast massive ldif load

Hello,
What is the fastest way (in terms of openldap settings) to perform a
massive load (~200MB ldif file) of data into openldap directory?
During load operation, no read/update operations will be performed,
only simple load. I start the process from command line:

ldapadd -xvc -D "cn=Manager,dc=progettotrio,dc=it" -W -f
20090910152733_output.ldif

Thanks,
iz1ksw