There are several of factors in database search performance, not the
least of which are disk/CPU speed and amount of RAM available (searches
are VERY memory-intensive).  Limiting the search is possible of course
(limit by date range or by narrowing your search terms).  I'd guess
though that your LISTSERV machine is memory-starved (probably paging
like mad to get enough memory) or just slow.  Not knowing what host
you're talking about I can't say one way or the other.

You might consider upgrading to the 1.8d release but I don't think that
will speed anything up per se.  Usually search slowness is due to the
factors mentioned above more than anything else.

Nathan