There are a few options I can choose when I setup my PHP environment for my Web Site here.
- APC – Alternative PHP Cache
It is used widely. Free, Open Source framework that caches the output of the PHP bytecode compiler in shared memory. Reduced parsing and disk I/O overhead for later requests.
The latest version is 3.1.13 beta released in Sep. 2012. Support up to PHP 5.4. It is a kind of abandoned project. So if you want to use PHP 5.5, better forget it, even it was the best before.
XCache is a fast, stable PHP opcode cacher that has been tested and is now running on production servers under high load. It is tested on Linux and FreeBSD and supported under Windows, for thread-safe and non-thread-safe versions of PHP. This relatively new opcode caching software has been developed by mOo, one of the developers of Lighttpd, to overcome some of the limitations of the existing solutions at that time; such as being able to use it with new PHP versions as they arrive.
It is an active project. Now the latest XCache 3.1.0 support PHP 5.5. It is easy to install XCache from source or from repos.
Accelerator is a free open-source PHP accelerator & optimizer. It increases the performance of PHP scripts by caching them in their compiled state, so that the overhead of compiling is almost completely eliminated. It also optimizes scripts to speed up their execution. eAccelerator typically reduces server load and increases the speed of your PHP code by 1-10 time
eAccelerator is also an older project, which moved to Github on July 25, 2012. The current master branch 0.9.6.1 supports PHP 5.3. it is released in 2010. I don’t think anyone should choose this tool.
- Zend Opcache (ex. Zend Optimizer+)
Zend Opcache is an open source component of Zend Server and Zend Server Community Edition.It speeds up PHP execution by opcode caching and optimization. it stores precompiled script bytecode in shared memory. This eliminates the stages of reading code from the disk and compiling it on future access.
Starting with PHP 5.5 the Zend Opcache is integrated and shipped with PHP. Even with PHP 5.4, Zend Opcache can be added easily. The latest ZendOpcache 7.0.3 here.
Only supports PHP 4. No new versions on the download page since Jan. 2003.
So actually, only two tools are available for long term usage. They are XCache and Zend Opcache.
I chose Zend Opcache on my VPS. Here is the phpinfo()