Google PageSpeed Insights score differs from dev tools

3
votes

I've got different results running Google Page Speed Insights (mobile) from Chrome Dev Tools and Google Page Speed Insights page. When I run Audits Performance (mobile, 3G) from Chrome Dev Tools I get higer score than "official page". Running from Chrome dev tools it says that I've implemented some optimization but running the test from Google Page Speed Insights page it suggests that optimization. I've tried test in different timing but the score on Google Page Speed Insights are always lower than Chrome dev tools.

I've implemented some optimization like "defer images not in view" with a lazy loading, I've deferred the css loading but only Page Speed in Chrome dev tools recognize this optimizations.

Can someone help me with this?

1
pagespeed-insights
Hi @Ivan, I experiencing a similar problem. Not with those checks of performance but with other ones. I detected a problem with Lighthouse versions (the one that Chrome runs vs the one PageSpeed is running). I posted a message on PageSpeed Google Group: groups.google.com/forum/#!topic/pagespeed-insights-discuss/… When I get an answer, if it's related, I'll post here the problem and resolution - OscarDOM
I discovered the same thing as well. Though both supposedly use Lighthouse to generate the report the results can be quite different. Some consistency would be nice. - Telarian

1 Answers

0
votes

I've been having the same issue and I guess the reply here is in this guide at the following FAQ:

Why do the field data and lab data contradict each other? The Field data says the URL is slow, but the Lab data says the URL is fast!

The field data is a historical report about how a particular URL has performed, and represents anonymized performance data from users in the real-world on a variety of devices and network conditions. The lab data is based on a simulated load of a page on a single device and fixed set of network conditions. As a result, the values may differ.