I have a section -> table -> data page -> report definition which returns 500 rows.

With 'Personalize table' allowed, I have 4 saved views which show the data with 1, 2 and 3 columns grouped, and with no columns grouped.

Why do the views with groups take 4 seconds to refresh (irrespective of number of columns grouped) where the view with no grouping takes 1 second?

thanks