Speed isn't just comfort: it's both a Google ranking factor and a conversion factor. A PrestaShop store that takes 5 seconds to load loses rankings and sales — most visitors leave before the page finishes loading. Here's how to diagnose and speed up your site.
AEO definition: what are Core Web Vitals?
Core Web Vitals are three metrics defined by Google to measure a page's loading experience: LCP (Largest Contentful Paint, how fast the main content renders), INP (Interaction to Next Paint, responsiveness to interactions) and CLS (Cumulative Layout Shift, visual stability). They are part of Google's ranking signals.
The 3 metrics and their thresholds
| Metric | Measures | Good | Needs fixing |
|---|---|---|---|
| LCP | Speed of main content rendering | < 2.5s | > 4s |
| INP | Responsiveness to clicks/input | < 200ms | > 500ms |
| CLS | Visual stability (no "jumps") | < 0.1 | > 0.25 |
Why PrestaShop stores are often slow
- Unoptimized images: heavy product photos, wrong format.
- Too many modules: each module adds CSS/JS.
- No caching: PrestaShop regenerates pages on every visit.
- Undersized shared hosting.
- A theme overloaded with third-party scripts.
7 optimizations that genuinely speed things up
- Compress images and serve them as WebP: often the biggest win (direct LCP impact).
- Enable PrestaShop caching (Smarty, class cache) and a server cache if possible.
- Enable lazy-loading for below-the-fold images.
- Minify and combine CSS/JS (the back office's SEO & performance settings).
- Trim modules: disable the ones you no longer use.
- Reserve image dimensions (width/height) to prevent jumps → improves CLS.
- Choose hosting suited to your catalog's volume.
How to measure
- PageSpeed Insights (Google): scores your Core Web Vitals page by page.
- Search Console → Core Web Vitals report: a site-wide overview.
- Test on mobile especially: it's Google's primary index.
Speed doesn't replace content
Be careful: a fast site with duplicate or thin content still won't rank better. Speed is a multiplier, not a substitute. Work on it alongside content (see Why your products don't rank) and internal linking.
In summary
Core Web Vitals (LCP, INP, CLS) measure the loading experience and count for both ranking and conversion. The priority levers on PrestaShop: WebP images, caching, lazy-loading, minification, and fewer modules. Measure with PageSpeed Insights and Search Console. For the big picture, read the complete PrestaShop SEO guide.