SweepPress Performance Control
Depending on the database size, some of the estimation and cleanup query can take a long time to finish, and some panel can be unresponsive because of that. All the sweepers that can run into this kind of problem have a High System Requirements, have a special mark on the Sweep panel.
To try and remedy that problem, plugin has special features that deal with the performance optimization of the estimation process. There are several options on the Settings panel to handle this.

Estimation Methods
There are several estimation methods available. It is best to have it set to ‘Automatic’, because plugin will decide what to do based on the database size. But, there are options to have estimation run on request for some (or all) sweepers. This will show the notice on the Sweep panel that will have a button for Sweepers to run the estimation when you want, and avoid running all estimations at once.

Estimation Calculations
All estimations can be run in ‘Full Mode’, where you will estimate data size and number of records to remove. Estimating size on the large database can increase the time needed for the estimates queries to run, and that can increase the time needed to show the overviews for the dashboard and the Sweep panel (and other relevant plugin features).
And, estimations can include the size of the Index for every result’s set. With this option, all size estimates will include the factored correction for the size to include approximated index size of the affected data. This works only with Full Mode estimations enabled.
Finally, you can cache estimations for a period of 2 hours. This is highly recommended for large databases.