In order to speed the activation for aggregates, follow the procedure:
1. Make a search of the cube
2. Righ click and chose “Manage”
3. Go to “Performance” tab and click in “Refresh Statistics” button
Monitor this backaground job in SM37 and once this job finish, you can start with the aggregates activation.
Go to “Roll up” tab and click in “Aggregates” button
Select all the Aggregates on the right side as showed below
Click in the match icon “Activate and fill”
The next window will appear
Click in the green arrow to “Fill aggregate”
Chose option “Now” to start immediately
Then a job is scheduled
Close the window.