When scrolling (e.g. with mousewheel) and a graph that was previously outside the view area moves into the view area there is a significant delay before the graph is drawn (1+ sec). If there are several graphs there is an even worse delay.

The workbook is not complex and the same spreadsheet in Excel (for Mac) 2008 did not suffer such delays i.e. nothing to do with the volume of data or the spreadsheet - something to do with Excel 2016.

I've not tried different styles or types of graph, mine are just simple line plots based in data in the same sheet as the graph (the workbook has only the one sheet anyway.

It may be related to the abysmal mousewheel scrolling. Unfortunately it is difficult to test due to bugs in the scrollbar slider positioning (try and move the slider and the position jumps way off from the displayed area - so the vertical positioning of the slider is bad and it takes ages to scroll back to the graphs. However, when mousewheel scrolling you do see a grey box where the graph should be whereas with the scrollbars, by the time you get back to the graph/data areas there is is instant graph draw - but the software has had ages to sort things out as you scroll back to the desired position (please please fix some of these bugs)