APC (Alternative PHP Cache for bytecode caching and object storage) isn’t bundled with Windows.
This seemed to work (basic test on PHP 5.4.11). This Stackoverflow answer was helpful.
- Download a DLL from http://windows.php.net/downloads/pecl/releases/apc/3.1.14/
(php_apc-3.1.14-5.4-ts-vc9-x86.zip at the time of writing) - Put in php/ext dir
- Add extension=php_apc.dll to php.ini
- Restart Apache
Other pages with Windows DLLs linked from that Stackoverflow discussion did not work for me.