Google’s Search ranking algorithm takes into account a number of factors when ordering results. The latest signal that will soon be factored in when ordering mobile Search results is page speed, though there are some key caveats.
Since 2010, Google has used page speed as a signal for ranking desktop Search results. In applying to mobile, there has been a fear that Google would use it to prioritize sites that take advantage of its Accelerated Mobile Pages.
However, that is not the case with this application. The “Speed Update” is only using the page speed signal to measure and look for the “slowest” experiences. According to Google, it will only affect a small percentage of queries.
To further allay fears of AMP prioritization, Google explicitly notes that it will apply the “same standard to all pages, regardless of the technology used to build the page.”
Meanwhile, Google will sometimes prioritize the intents of search queries so slow pages “may still rank highly if it has great, relevant content.”
This Speed Update is going live beginning July 2018, with Google encouraging developers to use resources like the Chrome User Experience Report, Lighthouse, and PageSpeed Insights to measure their pages.