I tried to setup a snippet
as you suggested and found that the regression is caused by the rendering of
the category axis labels.
What I've found is that the
chart renders at least ten times faster (which is really good!) if there are no
labels at all.
function (al lot of calculating if and where to put labels) and set the step
property for the labels accordingly from 1 to appropriate value (6, 12, 48,
720) based on chart width, amount of data, …
My suggestion is to state
in documentation that if the chart renders slowly use label settings (step property) to speed