I noticed on my computer (without any other changes) that when in Publisher 2013 I disable the 'Page Navigation' that all went smoother. Thus is as well the significant difference between the older versions and the newer version. Since each page in detail
is shown in the 'thumbnail' version of the site. And takes a long time until all is loaded (in the first go a lesser detail version and then in the second go a detailed version and probably the whole detailed page additional shown).
One can alternative with either CTRL+PageUp or CTRL+PageDown navigate between those pages or use CTRL+G to directly go to the different Pages.
So what happens, when you disable 'Page Navigation' in Publisher 2013? (Ribbon\View\Show\Page Navigation)