By default, all new servers come pre-installed with memcached, APC, and Varnish. All new Content Management System app installs will have them already configured and enabled. You may verify memcached is running on your server by typing the following from the command line (or web terminal).
If a process ID is returned, you know that memcached is running on your server.
Likewise, you can follow the instructions here to create a phpinfo.php page to display information regarding related PHP settings of your server.
For more information regarding memcached, visit the official project site.
If you have any questions or need further assistance, please contact support.