A handful of Email Marketing users reported a slower archive with Email Marketing 4.7.  We tracked down the issue and 4.70.2 takes care of that along with a couple other issues.  The speed issue occured on certain systems and was often due to older installs that have been upgraded time and time again in the past.
We encourage all users to upgrade to 4.70.2 to increase the speed of the archive.  If you continue to have any issues please submit a ticket and we will assist you right away.