XCache

XCache is a PHP opcode cacher. It improves performance for PHP applications by caching compiled PHP code in memory for later requests.

More information can be found on the website: http://xcache.lighttpd.net/

Availability
XCache is an on-demand available option to DreamHost PS users, on a per-domain basis, or can be setup for all domains to use it.

Configuring XCache
If you can view XCache through phpinfo, then you can configure it through a custom PHP.ini file by using the following settings: It can be added after the Zend Optimizer settings.