Within embeddedCAD, enabling IPN seems to make the whole program stutter, particularly when there's more than a handful of points.
I know this isn't a problem with normal MSCad.
We actually just looked into this one, and it's related to some of the background AutoCAD functions, like the highlighting, hover tooltips, etc. Keep an eye out for which tool might be causing it - it will be a little bit of trial and error, but maybe you'll notice which one is causing the issue for you. It's equally as tough on our end to determine which is causing it, since we don't have access to the code of the AutoCAD engine for debugging. We will continue to monitor it, and fix it when we can.