Memcached is a caching daemon to accelerate the request to Websites with high volume of visitors, used specially to accelerate and protect databases.
If your server has been installed the PCRE memcached extension and the libmencache, you can enable Memcached by filling the following fields with the proper data.
If you leave empty, fill them with incorrect data, or your Webserver does not support Memcached, the default Smarty Cache handler function will be used.