Built-in Addons:

OPcache

OPCache is powerful extension for PHP that will improve the speed of PHP page execution by caching scripts to improve speed and save memory. But, depending on the server setup, it can happen that OPCache can cause problems if the cache is not properly cleaned when scripts are updated.

GD Press Tools Pro adds very useful option to clean the OPCache (from the toolbar menu), and integrates panel with OPCache data in the information panel.