SLICER ISSUE-Pre-Loading all data

I have a report that when open in report server displays a blank page until the end-user selects dates in the slicer. This works great because it is not pre-loading all the data and calculations into it as there are several measures.

I was asked to create a similar second report and did so. On the second report it is pre-loading the entire dataset when nothing is selected in the slicer for some reason and this takes a little while. Is there any reason someone could think of that it is doing this on the one report and not the otheri if the layout and formulas are identical? It is driving me nuts. Any help would be appreciated.