Site Speed

Google’s mobile ‘Speed Update’ will try to get a full picture of your site’s performance and will use a variety of different metrics. JavaScript shouldn’t be an issue if you are using pre-rendering on mobile.

For JavaScript rendering, Google judges speed in the same way as it does for any web page. Sites being slowed down by JavaScript are only a problem when they are really slow, a matter of seconds doesn’t matter.

The Mobile Speed Update will only apply to mobile search results so desktop results won’t be affected.

Google looks at the overall picture when assessing site speed because optimising for individual metrics such as Time to first byte (TTFB) might not acually improve the overall experience for users.

Separate mobile sites need to be able to be crawled at the same speed as on desktop so if your separate mobile site is hosted on a slower server then this will affect Google’s ability to rank it after mobile-first rolls out.

Google’s page speed update for mobile search ranking will take into account metrics that map fairly well to Google’s existing tools, but won’t use them directly.

Google’s page speed algorithm will only affect mobile search results pages, not desktop search results.

Google doesn’t use the time taken to crawl a page as a measure of speed. Google tries to understand what a user would see, rather than what Googlebot sees, by looking at the time pages take to load and render.

Google may make speed a more important ranking factor when they get to closer to announcing updates around mobile.

Google only differentiates between slow sites and those in the normal range. However, looking outside Google’s algorithms, speed is very important for user experience, especially on eCommerce sites where a couple of hundred milliseconds can make a difference.