Hi,
I assume that you have problems with the speed of your queries on your cubes.
Analysis Services:
On each cube you have option (right click) Usage Analysis.
If you choose this, you can see how long it takes for each query to show the data to the user.
See which queries are problematical.
Then go, once again right click on the cube and choose option Usage-Based Optimization.
Now you can add aggregates to the existing ones only for thoose problematical queries.
Be aware that this aggregations don't stay when you reproccess your cube. You have to do this optimization regulary!
I hope I helped, please notify me if it worked for you.
Bye,
Andrej