David,
Thanks for your query. We are unable to observe any decrease in performance. We will further look into it. Meanwhile can you kindly create jsfiddle with the code that you are using and share the following info so that we can properly look into it.
1. OS details (Name and version)
2. Browser details (Name and version)
3. Zoom-level/panning at which you find performance issue.
—
Vishwas R