&reftitle.intro; OPcache improves PHP performance by storing precompiled script bytecode in shared memory, thereby removing the need for PHP to load and parse scripts on each request. This extension is bundled with PHP 5.5.0 and later, and is available in PECL for PHP versions 5.2, 5.3 and 5.4. &reference.opcache.setup; &reference.opcache.reference;