PHPBuilder.com has a few tricks up its sleeve when it comes to making your web pages as speedy as possible, and in their latest article, they've decided to share. It's part of an excerpt from the book "PHP 5 in Practice" from Eli White III and Jonathan Eisenhamer (Sams Publishing).
Often PHP is used to generate pages that do not change all that often. It isn't that PHP is used to make every page different for every user but that the page is simply built dynamically. In these situations, it is often the case that, the page really doesn't change all that often, perhaps only once a day, if that. In these cases, therefore, it is a waste of CPU time to regenerate the web page for every user.
In this situation, instead, we are going to create a dynamic solution. Some code that you can include at the top of every PHP file ensures that the page only gets generated once per hour for each script (see Listing 9.6.1).The function goes one step further and understands that different GET and POST parameters generate different pages and will therefore generate separate cached copies for each different combination of GET and POST parameters that occur.
They include a link to the source for the buffering and include an exmaple of its usage to get you started.