Best way to optimize for authenticated user performance?
Every site is different, thus it will require different tricks to get it working. Here are the ones I use for our sites for logged in performance.


http://drupal.org/project/dbtuner
http://drupal.org/project/advagg  
http://drupal.org/project/labjs  
http://drupal.org/project/css_emimage
http://drupal.org/project/imageinfo_cache
http://drupal.org/project/cdn


If you REALLY want to know what is causing the slow code, get a cache grind of your site. What all contributes to drupal page execution time?

edit: Looks like the 7.x version of Auth Cache is starting to be developed. Haven't used it but something to look into.


http://drupal.org/project/authcache