Real-time graphs: LineSeries.Points.AddRange VS LineSeries.ItemsSource

I am upgrading my static graphs application to real-time graphs. My data object (which I wrote, therefore I can change in any way necessary) exposes a property IList<DataPoint>. Now that it is a real-time data, new DataPoints will be appended to it continuously. If I think in WPF way, I think I should bind that property to LineSeries.ItemsSource and let it take care of updates (though I have to call InvalidatePlot()), right? But it seems calling AddRange() with only newly added DataPoints (though I have to separately create such a list each time just to pass it to AddRange) seems to be more efficient; am I correct?

Slightly off-topic but I could not really find a good example of real-time graph with latest version of OxyPlot. In order to implement real-time graphs, I have to periodically call AddRange(), move the visible range of the time axis, and call InvalidatePlot(); am I correct?

 If you could add such an example to the home page, that would be very helpful.