I figured out a solution that cut down the load time from around 20 minutes to 20 seconds:
1. Install the “WP Custom Admin Interface” plugin
2. Add this CSS to the “Add custom CSS to the WordPress admin” area:
#poststuff { display:none; }
3. Add this JS to the “Add custom Javascript/jQuery to the WordPress admin” area:
$(function() {
$("#poststuff").show(0);
});
I researched the slowness using Chrome’s Performance Profile and found that the majority of the time was spent on force reflows of the content. The above works because all areas of the page that are getting repeatedly re-rendered are hidden so the browser never has to “think” about where everything gets painted. When everything has been loaded it is then told to render everything – once!
