I am in the process of migrating a collection of reports from native SSRS 2005 to SSRS 2008 R2 integrated with SharePoint 2010 Enterprise. Reports that render within a minute in 2005 will not render in 2008 and usually crash the browser. I have checked the Execution log and the reports are completing within roughly the same amount of time, but the report in 2005 is 100K in size and the report in 2008 is 84MB in size. I am using IE8 to render the reports and I saw some information saying that this can be a problem. I upgraded to IE10 and the problem persists. I have also read that upgrading to CU7 for SQL Server will take care of it, but that is not the case for me. The latest recommendation is to turn off autogrow for all cells in the tablix. That did not help either.
I am looking for some suggestions about how to diagnose, what to look for, or how to fix.