Add the following line to it (after lines of code about the database is a good place):
define ('WP_CACHE', true);
Download one of the caching systems available at http://neosmart.net/dl.php?id=14. If you don't know which one you need, just download the basic file-based version.
Upload the files to the
/wp-content/
folder.Now you're good to go. Make sure everything works as normal. In day-to-day use you shouldn't see much of a change in speed, but once you get a lot of users, it will make a big difference.
Your WordPress MU and BuddyPress sites now use a cache to reduce server load. The cache is used as a way to store frequently accessed data in an easy-to-read file instead of in the database. This means that when a lot of people request the same page at the same time, instead of having to make lots of connections to the database, read out what it needs, and process lots of PHP code, the server can just...