
If you check your website speed on Google PageSpeed Insights, it is more likely that the mobile scores are lower than desktop scores. In this post, we shall cover the details of why is mobile usually lower than desktop on scores.
There are three main factors for this difference in Mobile vs. Desktop scores
- Google PageSpeed Insights simulates the mobile network at a slower speed over a 3G connection
- Mobile Devices generally have slower processors
- Mobiles have device specific CSS rules and the rendering is different on different browsers (resizing images in the browser, viewport size, etc.)
When you test the websites on mobile vs desktop over the same WiFi connection, then the scores will be similar. Unfortunately, Google PageSpeed Insights and Lighthouse always considers mobile connection to be a 3G connection. But, in reality the scores could be almost the same especially if it is run on WiFi. To bypass this 3G issue, you can use Lighthouse without simulated throttling checked and then both the mobile and desktop scores should be similar.

Google says that the bounce rate increases drastically to 80% if the load time increases from 1 second to 5 seconds. Speed is undoubtedly an issue that all publishers struggle with and it will not go away anytime soon. Website speed is central to the user-experience of the website and it is very dear to Google.

Google webmasters have said that the most important aspect of site speed is for publishers to make their websites perceivably fast for users. Page speed is probably the purest of SEO factors, because addressing loading times improves your rankings, your user experience and your conversion rate too.
When it comes to SEO, page and site speed has become an essential part of how search engines rate your pages.
That’s because Google doesn’t want to deliver results that are slow loading and put users off. They’re trying to present the most relevant, most appropriate websites with their results.
Hope this is useful, thank you.