When you use a CDN, it will improve performance for visitors that are located far from the server where your website is hosted. So the way to check the effectiveness is as follows: 1. Start with RocketCDN deactivated. 2. Run a few tests using GT Metrix (using a free account), Pingdom, or WebPageTest from a testing location far from your server, to get an average result. 3. Reactivate RocketCDN 4. Run several more tests using the same tool and the same server location as before and compare the load times. It's important to run the test multiple times to ensure the files are cached on the CDN server. In the screenshot below, the test site is hosted in Europe, so we compared the load time from Vancouver to see what difference the CDN would make. As you can see, it's about 1 second faster. 5. Specifically,  compare the load time of the same file with and without RocketCDN. You should see that the file is served much faster from the CDN. In the screenshots below, compare the difference in loading time of the 3 underlined files. You'll see that the ones served from RocketCDN are much faster. These are the results with RocketCDN: These are the results without RocketCDN: