How to speed up apache with mod_pagespeed and Memcached on Ubuntu 16.04

This tutorial will show you how to improve the page load times of your website by using the Google mod_pagespeed module for Apache in conjunction with the fast in-memory cache Memcached on Ubuntu 16.04 (Xenial Xerus). The page load time is an important factor to get good rankings in search engines, you can test the current load time e.g. with the Google PageSpeed Insights tool or with the developer tools in the Firefox web browser. Pagespeed is an Apache 2 module that optimizes and caches the content of a website before it gets delivered to the browser, the result is that the page loads, the system load on your server decreases and the server will be able to deliver more pages per second.