Separate all my content
Separating your tpl.php files in that manner won't improve your site's performance in the way that you hope, unless your current base node.tpl.php file is doing something really weird right now.

Loading more tpl.php files in a single page generally makes things slower not faster, as more hooks are invoked for preprocessing, etc...

Chances are, that if you have a 1-pager the tpl.php file being processed is not slowing your site down. It will be something in the database layer or excessing php processing, or incorrect caching setup.

If you still really want to do it, try Nikhil M's link to get the template naming suggestions.