1. Server Environment: Ratchet PHP is a library that allows real-time bi-directional communication between clients and servers using WebSockets, while XAMPP is a software package that includes Apache, MySQL, PHP, and Perl, creating a local development environment for web applications.
2. Usage: Ratchet PHP is specifically designed for building real-time web applications that require WebSocket connections, whereas XAMPP is used for general web development that involves PHP, MySQL, and Apache.
3. Technology Stack: Ratchet PHP is focused on implementing WebSocket connections and does not include a database or server software, while XAMPP provides a comprehensive environment with a web server (Apache), a database server (MySQL), and a server-side scripting language (PHP).
4. Ease of Setup: Setting up Ratchet PHP may require additional configuration and setup compared to XAMPP, which comes as an all-in-one package with easy installation steps for beginners.
5. Scalability: Ratchet PHP may offer better scalability for real-time applications due to its focus on WebSocket connections, while XAMPP may be more suitable for smaller-scale projects or local development environments.
6. Community Support: XAMPP has a larger user base and community support due to its popularity as a local development environment, while Ratchet PHP may have a more specialized community focused on real-time web applications.

In Summary, Ratchet PHP and XAMPP differ in their focus on real-time communication, technology stack, ease of setup, scalability, and community support.