It has been long known that Google takes into account the speed of your website in it's page rankings.

The just released Joomla 3.5 with Php 7 has shown to increase you website speed greatly.
We did a test and page load speeds where cut in half.

Before Joomla 3.5 Php 7 upgrade.

Before Joomla 3.5 Php 7 upgrade.

Allaroundyou Before Php7

After Joomla 3.5 Php 7 upgrade.

AllaroundyouAfterPhp7v2

 

Joomla 3.5 and Php7 something you should look into.