Install APC for PHP 5.5x in WampServer

Download APCu for PHP 5.5x

http://pecl.php.net/package/APCu/4.0.6/windows

Extract and copy php_apcu.dll to PHP extension directory

C:\wamp\bin\php\php5.5.12\ext

Enable APC extension in php.ini

extension=php_apcu.dll

Restart Wampserver