Late response. I am also experiencing this, where I try to plot scientific data with thousands of points. Intitial drawing of a plot is slow, after that it is a tad better. Two things I have found: .chartXScale and .chartXVisibleDomain don't work well together, and I got rid of .chartXScale. Setting a really high initial value for .chartXVisibleDomain improved the lagging. But it still lags. Seems like the framework is not really intended for large data sets.