Reports run slower in Excel 2007, 2010, or 2013 than they did in previous versions.
Disable multi-threaded calculation in the Advanced section of the Excel Options for the workbook that is experiencing the problem. Please note that this is a workbook (not application) level setting.
Although this may seem counter-intuitive, disabling multi-threaded calculation can result in a significant performance improvement for certain reports. Excel User Defined Functions (UDFs), such as the Jet Reports functions, are not always evaluated in the correct order of Excel’s calculation dependency tree. As such, if a function is evaluated before one of its dependencies, it will have to be recalculated after the dependency has been updated. We have found that this out-of-order calculation may occur much more frequently when multi-threaded calculation is enabled, resulting in multiple recalculations of a single function which leads to a dramatic increase in report run time.