When you first install and activate WP-Super Cache plugin it does almost nothing to increase your site speed.  In this video we show you how to adjust the settings for WP Super Cache so that it serves up the website faster for users, while still allowing administrators to see their updates without refreshing the cache.

Note that in the video I set preload mode to load every 120 minutes. We now recommend setting this to 360 minutes.

http://www.youtube.com/watch?v=c6wswM1MQUM

See also “How does a cache make my website faster“.