Most users will benefit from this module. It's actually a collection of patched files, optimizing the most called methods and functions. On average I am seeing an 8%-10% boost on all pages. I've tested a system with Apache bench and found that requests per second increased by 0.8 on this test machine. Your results my vary, tweak your apc .ini settings.
To install, just copy the files and folders onto your magento application, no files are overwritten, all the changed files go into app/code/local/*. To un-install, simply remove "Mage", "Zend", and "Varien", from app/code/local/.
UPDATE
Some users are reporting an error about calling a non static method statically. If you see see this error, just add the word ``static'' to
app/code/local/Mage/Core/Model/App.php
on line 944 so it looks like this
public static function useCacheStatic($type=null)
UPDATE AGAIN
It looks like some of this code has been integrated back into 1.0.19700. This module might not be necessary if you have the latest 1.0 installed. Also, be sure to remove these files before upgrading, as I'm not sure what trouble they might cause.
Features:
Version 2.0
Version 1.0
This file is considered a derivative work of the original Magento code and is therefore covered by OSL-3.0. If you do not agree to the terms of the OSL-3.0 do not proceed to download this code.