Google is giving increasing importance to the loading speed of websites.
In fact in the Google Search Console we already find the new speed report for the various pages that allows us to keep track of any slow pages and that need an improvement in terms of performance, perhaps because we forgot to have inserted too heavy an image or very large CSS files.
The Google Search Console will notify us via email, as we were already used to for other features, if some pages present problems as they are too slow..
The Google team is working to directly integrate a special 'badge' into Chrome that will mark slow sites, making it clear to a visitor that the site he is opening will load the page very slowly. Therefore the effect will be to encourage him to abandon that site for the benefit of another faster and more performing.
So not only a ranking factor, the loading speed of web pages will also become a sort of evaluation factor by users who use Chrome to navigate, who at a glance may be able to decide whether or not to click on the result of a SERP marked as slow, or whether to decide in favor of another faster.
Directly from Google in order to highlight any problems to be solved and the improvements necessary to increase the speed and performance of your website, this is Google PageSpeed Insights: https://developers.google.com/speed/pagespeed/insights/
The Google PageSpeed test generates a page performance report for both mobile and desktop devices and provides advice on the various aspects that should be improved. At the base of everything, there is a score assigned to the page evaluating the performances obtained, a real degree of classification. This score is determined through Lighthouse which is an open-source software from Google that can quickly analyze any URL address and produce a detailed report. The score is divided into 3 categories:
- Over 90: the page is considered fast
- Between 50 and 90: the page is considered average
- Below 50: the page is considered slow
The goal will be to avoid pages that fall into the third category with a score below 50, if we stay above this threshold our site will not be labeled as slow..
The best known plugin is definitely JCH Optimize available at this address: https://www.jch-optimize.net which is distributed in 2 different versions, one free and one paid PRO version..
For professional sites and for better results, we recommend the PRO version which includes much more advanced features such as the management of the HTTP / 2 protocol.
The plugn is available for the following CMS: 
Joomla 
WordPress 
Drupal 
Magento
