In most cases PHP performance can slow down the performance of websites. To optimize and accelerate website performance you need to improve the PHP performance. For this purpose, you can use opcode cachers such as eAccelerator, APC, Memcached, XCache, etc. Personally, my favourite choice is XCache.

XCache is a free, open source operation code cacher, it is designed to enhance the performance of PHP scripts execution on servers. It optimizes the performance by eliminating the compilation time of PHP code by caching the compiled version of code into the memory and this way the compiled version loads the PHP script directly from the memory. This will surety accelerate the page generation time by up to 5 times faster and also optimizes and increases many other aspects of php scripts and reduce website/server load.

May not be 5 times faster, but it will definite improves the standard PHP installation with the opcode XCaher. This article explains how to setup and integrate XCache into PHP installation on a RHEL, CentOS, Fedora and Ubuntu, Linux Mint and Debian systems.