[dfabulich]

> Although speed has been used in ranking for some time, that signal was focused on desktop searches. Today we’re announcing that starting in July 2018, page speed will be a ranking factor for mobile searches.

> The “Speed Update,” as we’re calling it, will only affect pages that deliver the slowest experience to users and will only affect a small percentage of queries.

The desktop ranking signal had almost no effect; slow pages reliably turned up in search results. Maybe some pages that took 15s to paint were slightly diminished in results, if that.

If the mobile ranking signal is as weak as the desktop ranking signal, (and they seem to be indicating it's going to be a very small effect,) I would expect this change to have no measurable effect at all on the median performance of pages loaded from Google search results.