We are on Sitecore 8.2 with MVC and datasources for our renderings. We have found that during development the adding/selecting of a datasource for a rendering is very quick, as one would expect. But on our test servers, and even in production, this is excruciatingly slow (1-5 minutes). I started to watch our resources on the machine in question and once a user creates a new datasource item the memory and cpu spike considerably. I am looking for possible causes to this issue or areas that I can make some improvements. We have not made any customizations to the pipe lines that are used when selecting/adding/creating datasources.
Thanks, Chris