One of the main reasons that pages can become slow to load (at least because of admin configurations) are the number of modules built on a specific page. When a module is attached to a page in the PAGES MANAGEMENT admin tool that module is "built" when a client browses that page on the client side. After building that modules functionality the script then places that output where that modules placement tag is within the design. Building the modules functionality is not a problem if you actually used that functionality within the design.

When you visit any of the pages within the PAGES MANAGEMENT admin tool you will find all of the modules attached to that page. As you develop your design in the page template and html modules the system will automatically attach modules it finds in any page template or html module. The problem is that the system does not automatically remove a module if it has been removed from the page template or html module. So after several changes and additions to a page template or html module adding and removing modules to get the design you want there may be several modules attached to a specific page but labelled "not found". It is then necessary to manually remove the "not found" modules so that they do not slow down the script.

When you save a change to a page template or html module within the admin tool that template or html is scanned for other modules within it. Once all of the modules are found every page that template or module is attached to is checked to see of the "found" modules are attached to those pages or not. If they are not already attached they are attached at that time. So if you use a module within a template or html module you will need to visit every page that template or html module was ever attached to remove that module if you decide later to not use that module in your design.

The only time a module may be labelled "not found" yet may still be in use on a page is if a module appears in a subcategory page template but not the default site wide template. You may need to manually attach modules that only appear in subcategory page templates to make sure that content is ready for placement in the design when that specific category page template is used.