If You're using 'Category List' view for Your menu item, it may be cause for the long time loading of Your page.
That happens because Joomla is starting (evaluating) content plugins for all articles from 'Category List', for category that You've selected (and Commedia content plugin too), even if Joomla will show only topics of those articles (without content).
To prevent it for Commedia You need to open
plugins/content/commedia/commedia.php and put after:
if ($jAp->getName()!= 'site') return true;
this line:
if ((JRequest::getCmd('view') == 'category') && (JRequest::getCmd('layout') !== 'blog')) return true;