SharePoint 2010 multiple report viewer webparts - very slow

Question

I have 7 report viewer webparts on one SharePoint page. It takes ages to load all of them. If I open the RDL directly, the report loads within 2 seconds. If I only load a single report viewer web part then the web part loads very fast too.

How can I decrease the loading time?

All those UpdatePanels that are created for lazy loading, AJAX calls, etc. cause part of the trouble. Disabling ViewState is not an option because it is breaking the web parts.

Answer 1

We've had the same problem over the years. SharePoint doesn't do well with multiple report viewer web parts. It's frustrating, but not much can be done about it. We found the best solution was to merge the different reports in a single report, essentially making the dashboard in the report itself. This reduced the number of web parts to one or two.