The only difference on both machines, is that in the one that is slow, i have created the database from an script, while in the other, the database comes from one backup in FB 1.03 and restore in FB 2.5. I will test both cases in my laptop this weekend.

Anyway is strange that the same script in the same machine, FB 2.1 takes 6 minutes and FB 2.5 takes more than 5 hours.

Jesus