Disable APC auto recompile modified PHP files
If you want extra performance boost for PHP/APC, you can tell APC not to auto recompile modified PHP files even they have changed. This can save APC for not to check the modification time of your script on every request.
To do so, edit your php.ini, and add
apc.apc.stat = 0
Restart your web server (e.g. Apache) to take effect.