I don’t think you can have more than one version of the index.php file... the Apache configuration explicitly lists the files that should fulfill the indexing function in its
DirectoryIndex directive. This is how some sites use a "default.html" instead of the more common "index.html"
For example:
DirectoryIndex index.html index.php index2.html
In that example, if you had an index.php and an index2.html both in the same directory, and you navigated to that directory, e.g.
www.yoursite.com/yourdir/, then Apache would serve up the index.php page because it’s defined first in the DirectoryIndex directive. If you deleted the index.php, then the page request would cause Apache to serve up the index2.html. If you put in an index.html in that directory, then the same request would bring up index.html because it has priority.
www.yoursite.com/index.html is technically a bit faster because you are explicitly asking for a certain file,
whereas www.yoursite.com/ is relying on
Apache to calculate which file should be returned. In that same vein,
www.yoursite.com/somedir is slightly slower than
www.yoursite.com/somedir/ because the trailing slash explicitly says that you’re requesting a directory, whereas if you omit that trailing slash, Apache has to figure out whether you are requesting a file or a directory, then once it figures out that you’re requesting a directory, it has to scan the directory for a valid DirectoryIndex.
Make sense?