To install APC follow the below instructions:
First, log in to the server as a root
Download APC


# wget


Extract and move into the directory


# tar xfz APC-3.1.3p1.tgz


# cd APC-3.1.3p1


Install some required dependencies:


# yum install php-devel pcre pcre-devel


Compile APC using:


# phpize


# ./configure


then run the following commands:


# make


# make install


Edit php.ini in regular way, add:


apc.apc.stat = 0
;apc.include_once_override = 1
apc.shm_size = 64


Restart apache. To check if APC is installed you may copy apc.php from same source directory to domain web accessible folder.
Open in browser . On that page you should see more Hits than Misses ( >90% is great result)

How To install APC