Thanks for the reply.The problem is after the sheet is loaded when i try to scroll down pivot table scroll bar,columns are frozen and it is taking time to display the data.I want to know if i can fix this.
Probably it is not solve to your problem, but I also note if there are a lot of dimensions and expressions in your pivot tables it takes time to reload data even you do expand or collapse.
How many dimensions and expressions hide in your reports? Can you simplify them. In my case, I split my information on a Table Box to reflect detail data (there were more than 100 columns totally) and creation set of pivot tables to calculate and reflect data by groups. It works faster than 1 pivot tables (I had about 10M files).