Why can't I see any difference on the speed of my website after installing the app?

I was expecting that this app would improve the load speed on my site but it seems that there is no difference at all before and after installing it. Why is this so?

Unfortunately, page speed applications such as Pingdom or GTmetrix will not show any improvements when Page Speed Optimizer is installed. This is due to the fact that these apps measure page speed on the first page when it is the first time opening the site while this app only starts working after the first-page load as we are preloading links on the page.