Is Zend Optimizer available?
Yes, Zend Optimizer is installed on all SiteGround's servers.
More information about it can be found by using the phpinfo() function. To do this, you should create a simple php file (e.g. phpinfo.php) with the following line in it:
<?php phpinfo(); ?>
and upload it on your hosting account. Then you should open this file in a browser to see the full Apache/PHP information and the Zend Engine details can be found on that page. The path to the file should be: