We suggest you to use the amazing tool webpagetest to verify the performance of your website in different location and with different browsers.
Step 1 – Compare the grade of the original website and the optimized website.
Note that you should go in the Advanced Settings and choose Number of Tests to Run : “10” with Connection : “DSL” to have more realistic times.
So, execute the test with your original domain
example.com and the optimized version
Step 2 – Perform a visual comparaison between the original website and the optimized website.
You can use this tool : http://whichloadsfaster.com/ to compare the two versions (click many times on “Go” to have consolidated results of many tries). Be aware that is a specific test limited to *your* browser, *your* connection, *your* machine.