WordPress vs Astro Performance

A recent analysis comparing major content management systems has shed new light on what actually drives real-world Core Web Vitals performance. The findings place WordPress and Astro at opposite ends of the spectrum, while also showing that performance is influenced by more than just page weight or Lighthouse scores.

The report, based on data from HTTP Archive and the Chrome UX Report (CrUX), examined how different platforms perform in real user conditions. It covered seven popular CMS platforms and challenged the assumption that lighter pages automatically lead to better Core Web Vitals results.

Why Core Web Vitals Matter

Core Web Vitals (CWV) are a set of metrics created by Google to measure user experience on the web. They focus on three key areas: loading speed, visual stability, and interactivity.

Although CWV is only a minor ranking factor, it plays an important role in user experience. Websites with strong scores tend to load faster, feel smoother, and encourage higher engagement and conversions. On the other hand, poor performance can lead to frustration, higher bounce rates, and lost traffic.

Because of this, CWV has become a key benchmark for developers, SEOs, and platform providers.

Page Weight vs Real Performance

One of the main assumptions tested in the report was whether page weight directly impacts Core Web Vitals performance.

At first glance, there does appear to be a connection. Lighter pages often perform better in CWV metrics. However, the data shows this relationship is not as straightforward as it seems.

For example, Astro had one of the lightest median page weights at around 1.65 MB, while Duda and Wix also kept relatively lightweight pages and performed strongly in CWV rankings.

However, Shopify complicated this pattern. Despite having the heaviest pages in the study at approximately 3.77 MB and lower Lighthouse audit scores, it still achieved one of the strongest real-world CWV performances.

This suggests that page size alone is not the defining factor in how users actually experience website performance.

How the Data Was Measured

The analysis combined two key datasets: the Chrome UX Report (CrUX) and HTTP Archive.

CrUX provides real-world performance data collected from users who opt into Chrome usage tracking. This reflects how websites perform under real conditions, including different devices, networks, and browsing behaviours.

HTTP Archive, on the other hand, uses lab testing to evaluate websites and measure technical performance factors such as page size and Lighthouse audit results.

By combining both datasets, researchers were able to compare theoretical performance against actual user experience.

Top Performing Platforms for Core Web Vitals

The results revealed clear differences between platforms.

Duda ranked first, with around 85% of sites achieving good Core Web Vitals scores. It also maintained one of the lowest median page weights, which supports the idea that lighter builds can contribute to better performance.

Wix followed closely in second place, with approximately 80% of sites scoring well. Its page weight was slightly higher than Duda but still competitive.

Shopify came in third with roughly 79% of sites meeting CWV standards. This was particularly notable given its heavier page weight and more complex site structures typical of e-commerce platforms.

Despite that complexity, Shopify continued to perform strongly in real-world metrics.

Shopify Challenges Expectations

Shopify’s results stood out because they go against the usual assumption that heavier websites perform worse.

E-commerce sites naturally rely on more scripts, dynamic features, product filtering, and tracking tools. These elements usually add weight and slow down performance.

However, Shopify appears to offset this through strong infrastructure. This includes stable rendering, efficient delivery systems, CDN optimisation, and careful control of layout shifts.

As a result, real users experience faster and more stable page interactions than expected based on lab results alone.

This highlights an important point: Core Web Vitals is not just about reducing file size, but about how efficiently complexity is managed.

Astro’s Strong but Context-Dependent Performance

Astro also performed well, with around 67% of sites achieving good CWV scores.

Its lightweight nature naturally contributes to strong performance, especially for simpler websites such as blogs or content-focused pages.

However, the data also suggests that this advantage may depend on use case. As site complexity increases, the gap between Astro and other platforms may become less predictable.

In other words, Astro performs strongly out of the box, but real-world results may vary depending on how it is implemented.

WordPress at the Lower End of Performance

WordPress ranked last in the comparison, with approximately 49% of sites achieving good Core Web Vitals scores.

It also recorded one of the heavier median page weights and lower Lighthouse audit results compared with other platforms.

This combination suggests that many WordPress sites may struggle with performance issues linked to plugins, themes, render-blocking resources, and overall execution efficiency.

However, it is important to note that WordPress is highly flexible, meaning performance can vary widely depending on how it is configured and optimised.

Why Lighthouse Scores Don’t Tell the Full Story

One of the key takeaways from the analysis is that Lighthouse scores do not always match real-world Core Web Vitals performance.

Lighthouse measures lab conditions, focusing on factors such as unused JavaScript, render-blocking resources, image optimisation, and simulated network conditions.

While useful, these metrics do not fully capture real user behaviour, including caching, repeat visits, CDN performance, or device variability.

This explains why some platforms with lower Lighthouse scores still perform well in real-world CWV data.

The Bigger Picture: Complexity Matters More Than Size Alone

The findings suggest that Core Web Vitals performance is influenced by more than just page weight.

Platforms like Shopify show that even complex, heavy websites can deliver strong user experiences when infrastructure and delivery systems are optimised effectively.

At the same time, lightweight platforms can still struggle if execution issues such as poor scripting, layout shifts, or inefficient rendering are not properly handled.

This shifts the focus away from simple size reduction towards smarter performance engineering.

Final Thoughts

Overall, the comparison shows that Core Web Vitals is not a straightforward contest of who can build the lightest website.

Instead, it is about how well a platform manages complexity under real-world conditions.

WordPress, Astro, Shopify, and others all demonstrate different strengths and weaknesses depending on how they are used.

The key takeaway is that reducing page weight can help, but it is not a guaranteed solution. Real performance depends on how efficiently a site handles loading, interactivity, and visual stability in practice.