Also, Gzip must be installed on your server and enabled in PHP in order to function.
What does this mean in the real world?
To see how this effects a template in the a real world scenario, we'll examine the front-page of the SolarSentinel demo site from a very average 768kb DSL connection. We used the Net panel in Firebug for Firefox to get our data.
First we'll see how the site loads the CSS without RokGZipper enabled:
As you can see because the SolarSentinel template allows for maximum flexibility with almost unlimited combinations of header/body/footer/backgrounds etc, there are multiple CSS files loaded as well as some of the CSS files needed for the modules used. Let's turn on RokGZipper and see what we get now:
As you can clearly see the 11 original requests have been reduced to 4 requests. The 104KB of CSS files has been reduced to just 18KB (17% of the original size!), and the original 1.44 seconds it took to download the CSS files has been reduced to just 359ms (400% faster!). A drastic improvement!