Why is my mobile PageSpeed score so much lower than desktop?

PageSpeed Insights does not test your site on the device you are using. For the mobile result, it emulates a modest phone with a slower processor and applies network throttling to mimic a mobile connection. The desktop test uses a faster machine and connection. The same page therefore takes longer to download and, often more importantly, longer to process JavaScript on the mobile test. A desktop score in the nineties alongside a mobile score in the forties is common for sites with heavy scripts.

That simulated phone is not unrealistic for Pakistan. Many visitors in Islamabad and Rawalpindi browse on mid-range Android phones, sometimes on congested mobile data in a market or while travelling between the twin cities. If the mobile test struggles, real visitors on such devices probably do too. Search Console's Core Web Vitals report separates mobile and desktop field data for this reason, and Google primarily uses the mobile version of your site for indexing and ranking.

To close the gap, focus on what hurts phones most. Reduce JavaScript: chat widgets, sliders, multiple analytics tags, and page-builder animations all cost processing time. Serve smaller images to smaller screens. Load fonts efficiently, and avoid hiding desktop content on mobile while still downloading it. Do not judge improvements by the desktop score, since it may already look fine. Our speed optimisation service reports both, but sets targets on mobile, and sites built under the Business bundle are designed on a phone screen first so the gap stays small.