Another name is PageSpeed Insights or “Make your web pages fast on all devices.”. This SEO tool uses data from the Chrome User Experience Report and display real-world performance. It will shoe following data: page load distribution, optimization score, page statistics and optimization suggestions. You get separate reports for desktop and mobile devices. And the results falls into three categories: fast, slow, average. Page speed is one of the metric google consider in it ranking and the faster your page loads, the lower the bounce rate would be. And when your site is fast, you have an advantage over slow sites. Check Google the top ranking websites they their pages loads fast. Use PageSpeed insights to check every major page of your site. You will get a valuable clues about what Google see and suggest improving. It is a good start on the path to get on the first page in search engine results page and it's FREE.