I have tried WPF DV and I am a bit deceived that panning won't show the actual data (or at least some approximation).

What I would like would be that after a small delay displayed data would be updated anyway so that the user would have some feedback while scrolling.

If performance is an issue, I might display only part of the information while in that mode (pan, scroll...). This could be either be done by displaying most important series first or by reducing the number of points while scrolling.