ez_cache

This script uses PHP4's output buffering to allow you to only cache certain parts of your page. Very useful if you want some items updated more often than others.

Toncarta Cache

Toncarta Cache is an output caching system for php scripts. It 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), and 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.

jpCache

jpcache is a lightweight, full page caching system for PHP which uses gzip content-encodig and ETag-headers. It allows around 80% in traffic-saving for php-pages and reducing server-load.

Zend Optimizer

The Zend Optimizer uses multi-pass code optimizations to double the running speed of PHP applications. This add-on is appropriate for all PHP users, who can benefit from the better response time featured by the product. The increase in speed for running PHP code reduces the CPU load for the server, and cuts in half latency time.