Site Cache  

Site Cache is a code cache system for PHP. It will increase the speed of your site via gzip compression and file caching. It cannot be used with any product already using gzip compression and is best used on a personal website, or corporate system for faster performance.

Hosting Requirements: Unix; PHP 4.0.4+
Price: £25

   Turck MMCache  

Turck MMCache is a free open source PHP accelerator, optimizer, encoder and dynamic content cache for PHP. It increases performance of PHP scripts by caching them in compiled state, so that the overhead of compiling is almost completely eliminated. Also it uses some optimizations to speed up execution of PHP scripts. Turck MMCache typically reduces server load and increases the speed of your PHP code by 1-10 times. Turck MMCache stores compiled PHP scripts in shared memory and execute code directly from it. It creates locks only for short time while search compiled PHP script in the cache, so one script can be executed simultaneously by several engines.

Hosting Requirements: apache 1.3, mod_php 4.1, autoconf, automake, libtool, m4
Price: Free

   morecache  

morecache is an output caching class. Use it to give your pages a big boost of speed.

Price: Free

   ez_cache  

This class uses php4's output buffering to cache only certain parts of your page.

Hosting Requirements: PHP 4
Price: Free

   RFKcache for PHP  

RFKcache is an easy and efficient cache engine for PHP programs.

Price: Free

   cgi_buffer  

cgi_buffer is a group of libraries (for Perl, Python and PHP) that automatically handle performance-improving HTTP features that most Web servers don't implement (at least for scripts).

Price: Free

   jpcache  

jpcache is a lightweight, full page caching system for PHP, thus reducing server-load, as pages are generated less often. It dramatically speeds up the serving of your pages, by caching the ouput of pages and returning them instead of compiling the php-page. It also uses gzip content-encodig and ETag-headers, which results in around 80% in traffic-saving for php-pages. You can choose to store the cached output in files in a local dir or in a database.

Price: Free

   Toncarta Cache  

An output caching system for php scripts. Cuts the load on your server(s) by caching the output of your scripts. Features: Can set a maximum age for cached data, exclusions can be set on a per file basis, 3 different storage types: database, file and shared memory. (Only db and file currently implemented). Data can be compressed if disk space is an issue. On a moderately complex php script (doing ~50 simple sql queries) it increased throughput by approximately 3 times. On more complicated scripts this figure can be expected to rise.

Price: Free

   APC  

APC is the Alternative PHP Cache. It was conceived of to provide a free, open, and robust framework for compiling and caching php scripts. APC was conceived of to provide a way of boosting the performance of PHP on heavily loaded sites by providing a way for scripts to be cached in a compiled state, so that the overhead of parsing and compiling can be almost completely eliminated. There are commercial products which provide this functionality, but they are neither open-source nor free.

Hosting Requirements: PHP 4.0.3+
Price: Free

   Zend Optimizer  

The Zend Optimizer is a free application that runs the files encoded by the Zend Encoder and Zend SafeGuard Suite, while enhancing the running speed of PHP applications. Benefits: Enables users to run files encoded by the Zend Encoder and increases runtime performance up to 40%.

Hosting Requirements: PHP 4.0.5+
Price: Free