Smarty-2.3.0/Smarty.class.php
Code:
var $caching = 0; // enable caching. can be one of 0/1/2.
// 0 = no caching
// 1 = use class cache_lifetime value
// 2 = use cache_lifetime in cache file
// default = 0.
var $cache_dir = 'cache';
By default x-cart will not cache any .tpl's
http://smarty.php.net/manual/en/variable.caching.php