Here is a short tip from our team that helps you optimize the page load speed.
In one of our applications we have a page listing patients of a practice. As the practices grew their business, we noticed a slowdown when loading that page.
The initial implementation was using a CArrayDataProvider with the data retrieved using an SQL query. Therefore the slowdowns' cause was that on every page load the data was retrieved from the database, and after only the 10 needed results were taken out and displayed. The solution was replacing the implementation with CSqlDataProvider