Mobile page speed score is 20 points lower than Desktop

  • I have tested my webpages over 100 times on Google Page Speed, but it consistently shows lower score for mobile webpages.

    I have 15 live web services on the same dedicated server (my own server in my office), w/ some shared and some diverse performance-related configurations for each one of them.

    Shared one

    • Nginx Fast CGI cache, along with typical Nginx configuration
    • Redis Object Cache

    Not shared ones

    • Cloudflare APO for some
    • Cloudflare free version
    • Super Page Cache for Cloudflare
    • WP Rocket / W3TC

    For about 5 webpages that I have heavily cultivated configuration settings, I have 97~99 on PageSpeed’s perfomance index on Desktop, but mobile version is suffering around 60~70. I hardly have 80 for mobile.

    I also have enabled separate mobile cache as a test, but whichever the variable option I have, it doesn’t reduce the gap. I suspect what people call ‘render blocking time’ is more severely damaging my webpage’s mobile loading, but have no clue what setting to blame and how to fix it.

    Would be great if anyone with similar experience can share me necessary steps that I have to take.

    To give you my side information, the highest score I earned (99 on performance) has following setting

    • Nginx Fast CGI
    • Redis Object Cache
    • Cloudflare free + APO
    • Super Page Cache for Cloudflare
    • WP Rocket

    For some pages that CSS/JS minification does not break, I use W3TC, which gives me more setting options.

    I keep all my images in local server, and wonder if this is the cause of suffering mobile pages.

    The page I need help with: [log in to see the link]

Viewing 6 replies - 1 through 6 (of 6 total)

  • You are lazy loading your LCP image. You need to exclude it from lazy loading, and preload it if possible.

    And you have a large DOM structure on this page, which also contributes to your PSI score/grade. You can look into content-visibility to improve your page rendering performance.

    Thread Starter Keith

    (@keithkhl)

    Well for the record, I do not have any lazy loading option turned on. I’ve just double checked my plugin settings, but it is clearly not.

    If images are lazy loaded, it is WordPress default setting.

    When it comes to DOM structure, I do admit it is heavy, but desktop performance is unaffected. Mobile pages have much simpler DOM structure, yet, I have much lower score on performance.

    If images are lazy loaded, it is WordPress default setting.

    You then need to disable the core functionality.

    When it comes to DOM structure, I do admit it is heavy, but desktop performance is unaffected.

    What works well on a desktop may not work with the same efficiency on a mobile, which could have a slower network, and less powerful CPU/GPU.

    Google PSI also throttles network and CPU, which you can see by hovering over “Emulated…” and “Slow 4G throttling”.

    Mobile pages have much simpler DOM structure, yet, I have much lower score on performance.

    DOM structure isn’t limited to what you see, it is what you have on the page. And according to Google PSI, you have “3,459 elements”. You are using 2 different layouts for mobile and desktop, and hiding either version doesn’t remove those DOM elements, it just hides it. Browsers still need to go through the entire DOM for rendering, processing, styling, etc.

    Thread Starter Keith

    (@keithkhl)

    well.. even with lazy loading turned off for a day, and even for a freshly created website without much of DOM structure, I have consistently lower score for mobile, and as @ashutosharma97 pointed out, it seems like it is due to slow image loading.

    Just wonder why cloudflare provides near 0ms lag in image loading for desktop while mobile loading is way slow. My personal experience with my own laptop/desktop/table/mobile in fact got significantly improved after applying cloudflare’s APO. There must be some sort of server level issue that delays mobile image loading from Google PageSpeed’s perspective.

    Just wonder why cloudflare provides near 0ms lag in image loading for desktop while mobile loading is way slow.

    That’s because Google throttles mobile CPU, and mobile network. You can read about it here: https://developers.google.com/speed/docs/insights/v5/about#what-device-and-network-conditions-does-lighthouse-use-to-simulate-a-page-load

    The mobile performance of “https://arkwellnessctr.com/” is commendable with a high PageSpeed Insights score of 96. Key metrics include a First Contentful Paint (FCP) of 1.9 seconds and a Largest Contentful Paint (LCP) of 2.2 seconds, both indicating relatively quick loading times. The Total Blocking Time (TBT) is an excellent 0 ms, ensuring high responsiveness, and the Speed Index is 3.6 seconds, showing efficient visual rendering. The Cumulative Layout Shift (CLS) is 0, reflecting a stable and visually consistent experience. While these results are strong, slight optimizations in image compression, JavaScript minimization, caching, text compression, and server response times could further enhance the site’s speed and user experience.

Viewing 6 replies - 1 through 6 (of 6 total)
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