By default Vuze automatically make a backup (resume data) of your actual downloads each five minutes. This allow the program to rapidly resume and interrupted (due to a crash, bad manipulation) download in a glance.
To modify the fequency at which Vuze updates resume data:
Open Vuze > Click on the Tools Menu > Options
Select the "File" tab
Enter a value in the field (e.g 1) next to "Update Resume data every"