google consider site load time in the site ranking and search ranking criteria

Hello Guys, as you know that i am QA and we consider the site speed as well in site testing, last time when i am working on the manual website testing then site speed is very slow and i get idea that is it reflect on the google. so i search on the google and knew that google consider site load time in the site ranking and search ranking criteria, so if you site loading speed is low then improve site speed, which increase the site performance and as faster your site load its get good ranking in google. i also read that google mention that they consider the site speed and they provide special tools in webmaster tools and using that you can check the speed and performance of your website.