I addressed BIE performance for a 2014.5 Adv client recently. Initially it wasn't too surprising as many of their data files are quite large, and at least in some cases the data goes back to 2003 therefore I suggested that they would probably benefit by performing some archiving/purging activities. However, it was also determined that creating saved filtered Views in BIE helps with the performance. Along with that, it looks like the ""automatically load data"" setting should be disabled so that the standard non-filtered Views don't attempt to auto-refresh and cause the user to sit and wait. Hence it would seem that we'd ideally want to be able to just go into BIE, have no data appear, and select the saved filtered View to run.