Written by: on 18 January 2018
From an official statement from Google, a slow page on your site may show up lower in ranking on mobile search query. Keep in mind, the intent of the search query is still a strong signal. So even though the site may have a slow page, the relevant content will place it higher. On the other hand, if the content is not relevant and the page speed is slow, you might want to seek other options as the slow page and slow site can be penalized.
Google already has a few tools out there to check performance of your site, one of them includes PageSpeed Insights.
PageSpeed Insights can be used to indicate how well a page performs. It also suggests performance optimizations that you can consider for your site.
Start taking advantage of this change early on as this ranking factor will start July 2018.