DayPilotCalendar has problems with performance when showing a lot of time cells.
The problem is that it was designed for the typical Outlook view, that means 30 minute cells, 24 hours a day, 7 days. That is 24*2*7 = 336 cells. All the cells are rendered as a single HTML table. When you switch to 6 minute cells and increase the number of columns (showing either days or resources) the table grows and the browser gets problems. The table DOM is created on the fly and both the DOM creation time and rendering takes longer and longer (it doesn't seem to be linear growth).
I could speed it up a little bit by improving the DOM creating code but that would only move the limit a bit further. The final solution will follow the model used in DayPilotScheduler reimplementation in DayPilot Pro 5.0. That means that only the visible viewport is rendered and the rest is created during scrolling.
This will be done with the next DayPilotCalendar rewrite (the time frame is 3-6 months).