To determine if the "cost" of an applications lies in the data model or the UI you can load the application binary into an "empty" qvw-file and then move objects over the new file to see if they perform better "on their own". Remove dependencies from variables, by expanding to text instead of relying on dollar-sign-expansion, to get the full view of the actual calculations the object require.
To test the data model you only need the binary load and some list boxes. Make some clicks and observe the behavior. It's also good to keep the Task Manager open as suggested in prior Quick Tip.
If you don't want to go that far, you can create a new sheet and move objects one by one. This will not give you the same isolation but it's still a good technique.
Cheers from the Scalability Team.