New Post: Performance Limits for SPCascadeDropdowns

I'm using the following versions:
jquery-1.10.2.min.js
jquery.SPServices-2013.01.min.js

I used IE8's profiler to look at the timings (it's the only browser available to me) and the main culprits appear to be GipRefreshGroupCore and GipSplit. These are functions within GroupedItemPicker, a SharePoint JS library. These two functions account for 75-80% of the load time.