Swift Performance provides an intelligent, modern caching system. You can even cache AJAX request, dynamic pages, and you can add exceptions (URL, page or content based rules). To achieve the best performance you have to optimize your images. Swift Performance provides a highly customizable, unlimited Image Optimizer. Keeping your database clean is extremely important for speed. Swift Performance has a built in DB Optimizer to maintenance WordPress database. One of the most important thing for performance is optimize the delivery of static resources. Swift Performance not only combines and minifies the CSS files, but generates the Critical CSS for each page automatically.