New SE with Jam, Slow Queries?

We use JAM with an Informix SE engine on a SCO Unix Altos 15000. We recently upgraded the Informix engine from 4.1 to 5.01 and the SCO Release from 3.2 v2.0 to 3.2 v4.1. Why would querying in general be noticeably SLOWER on the new system than on the old? We are using the same data set, migrated over. Is there some "tuning" we need to do to get it up to past performance? ********************************* Nick Nobbe, Library of Congress NLS/BPH Off: (202) 707-0548 Fax: (202) 707-0711 mail: nnob@seq1.loc.gov *********************************