Ugh, that's a lot of subreports.
One thing that may have changed is the SQL not being passed to the database, so check the Database->Show SQL Query in both versions for differences.
Also the connectivity might be an issue, since you're concerned with performance, you should always post your database type and the connectivity used, these are not incidentals, rather crucial details in determining the performance.
You might also be well served to select one particular report, and post technical information:
Database/connectivity
Means used to access data (as in the report GUI, vs. a Command vs. ADO, etc)
Post what's in the Database->Show SQL Query
Post what's in the Report->Selection Formulas->Record
The latter being what Crystal passes to the database if you're using conventional database access through the Crystal GUI.
-k