In a recent discussion on Reddit, Google Search Advocate John Mueller shared valuable guidance on optimizing website performance and the challenges of improving Google’s PageSpeed Insights (PSI) scores.

The Reddit thread in question involved a user who sought advice after making substantial reductions in image and video file sizes, but without the expected improvement in PSI scores. Despite compressing images by 90% and videos by 80%, the user found their website’s speed score remained unchanged.

For context, PageSpeed Insights is a free tool provided by Google to assess the loading speeds of web pages. It examines various elements such as images, scripts, and code to generate a score on a scale from 0 to 100 and offers suggestions for performance enhancements.
Given the significance of page speed in the realms of search engine optimization (SEO) and user experience, achieving a high PSI score is a priority for many website owners and developers.

John Mueller’s PSI Optimization Tips

Mueller recommends several strategies to boost PSI scores effectively:

  1. Conduct Individual Element Tests: To improve your PSI scores, Mueller suggests running tests to understand the impact of individual elements on your website’s performance. You can create a test page with one component, such as an image or video, and exclude it from search results using the noindex tag.
  2. Isolate Specific Changes: By isolating specific changes on the test page, you can measure their individual effects before implementing them across your entire website. This controlled experiment can reveal the performance gains achieved through compressed files.
  3. Identify Limiting Factors: If your test page doesn’t yield the same score as your live pages, it indicates that other factors are limiting performance. In such cases, Mueller recommends selectively removing elements that have already been optimized from a copy of the actual page to focus on enhancements for the remaining issues.
  4. Consider Acceptable Scores: It’s important to note that your website’s current scores may already be within acceptable parameters. If your page speed falls within a “reasonable” range, extensive additional work may not be necessary. While Mueller doesn’t specify what these parameters are, it’s essential to assess whether further optimization is truly required.


Enhancing website performance often involves incremental testing and a patient approach. When aiming to improve your PageSpeed Insights scores, consider isolating webpage elements to evaluate their impact before implementing changes across your site. By tailoring your strategies to your website’s unique requirements, you can achieve and maintain favorable performance scores.

Remember, optimizing website performance is an ongoing process, and with the right tactics, you can ensure that your scores remain in the green zone, ultimately benefiting your SEO and user experience.