WordPress 6.4 Performance Improvements  ## Metadata - Author: [[Emily Clarke]] - Full Title: WordPress 6.4 Performance Improvements - Category: #articles - Document Note: --- tags: - #wordpress - #performance - #core Author: Emily Clarke Source: WordPress Core Make Blog Reference: https://make.wordpress.org/core/2023/11/13/wordpress-6-4-performance-improvements/ date created: 2025-08-23 00:00 --- # Title: WordPress 6.4 Performance Improvements ## Table of Contents: - 🔗 [📝 Summary](#-summary) - 🔗 [📖 Main Content](#-main-content) - 🔗 [🗒️ Notes](#-notes) - 🔗 [📖 References](#-references) - 🔗 [🗣️ Paraphrase](#-paraphrase) - 🔗 [📰 Newsletter](#-newsletter) - 🔗 [✅ Action Items](#-action-items) - 🔗 [🧪 Hypotheses](#-hypotheses) - 🔗 [📊 Methodology](#-methodology) - 🔗 [❓ Questions](#-questions) - 🔗 [🔮 Future Research](#-future-research) - 🔗 [💡 Implications](#-implications) - 🔗 [🧠 Learning Styles Assessment](#-learning-styles-assessment) - 🔗 [📊 Accessibility Assessment](#-accessibility-assessment) - 🔗 [🌍 DEIB Assessment](#-deib-assessment) - 🔗 [✅ Logical validity](#-logical-validity) - 🔗 [🔍 SEO Evaluation](#-seo-evaluation) - 🔗 [🎯 Conclusion](#-conclusion) ### References: - WordPress 6.4 Field Guide: https://make.wordpress.org/core/tag/6-4/ - compare-wp-performance GitHub Action (example and docs): https://github.com/WordPress/wordpress-develop/tree/trunk/.github/actions/compare-wp-performance - Twenty Twenty-One theme: https://wordpress.org/themes/twentytwentyone/ - Twenty Twenty-Three theme: https://wordpress.org/themes/twentytwentythree/ ## 📝 Summary: WordPress 6.4 delivers measurable performance gains. Server response time improves by about 4% versus 6.3.2, with additional frontend optimizations boosting Largest Contentful Paint (LCP): ~4% better on Twenty Twenty-One and ~9% on Twenty Twenty-Three. The release continues server-side enhancements (object caching, options API functions, template loading) and client-side improvements (image/script loading and style handling). It also debuts a more reproducible benchmarking workflow using a standardized GitHub Action to compare versions across 100 requests, repeated five times and summarized by medians. ## 📖 Main Content: WordPress 6.4 caps a year of performance work with balanced server- and client-side wins. On the server, improved object caching and new options functions reduce database round trips and speed template resolution. On the client, smarter image loading and script handling, plus replacing hard-coded style tags with wp_add_inline_style, reduce render-blocking and improve Core Web Vitals—especially LCP. The team advanced methodology by automating benchmarks via a GitHub Action that spins up paired test sites with wp-env, runs 100 requests per run, repeats five times, and reports medians, improving reliability and reproducibility. Re-benchmarks of earlier releases with the new method provide cleaner comparisons across Twenty Twenty-One and Twenty Twenty-Three, showing consistent LCP and server timing improvements moving into 6.4. Future work targets stabilizing metrics, richer test content, and broader environments (PHP versions, persistent object cache). ### 🗒️ Notes - Performance outcomes - ~4% faster server response than 6.3.2. - LCP improved: ~4% (Twenty Twenty-One), ~9% (Twenty Twenty-Three). - Focus on both server and client optimizations to impact Core Web Vitals. - Server-side improvements - Object caching: fewer DB queries, better cache hits. - New option functions: more efficient get/update patterns. - Template loading: faster resolution and inclusion paths. - Client-side improvements - Image loading optimization: better lazy/eager balance to improve LCP. - Script loading changes: defer/async patterns, reduced blocking. - Styles: replace hard-coded tags with wp_add_inline_style for cleaner enqueueing and dependencies. - Benchmarking methodology - Transition from manual local runs to automated, reproducible CI workflow. - Uses compare-wp-performance GitHub Action with wp-env in GitHub runners. - 100 requests per run, 5 runs, medians reported; provides action summaries and links. - Comparative findings (re-run under unified method) - Consistent trend: LCP and server timing improve across themes moving to 6.4. - Data aggregated in a shared spreadsheet with workflow links. - Future improvements - Stabilize metrics further (variance control). - Expand test content and scenarios. - Systematically vary environment: PHP versions, persistent object caching, hosting profiles. ## 📖 References: - WordPress 6.4 Performance Improvements post: https://make.wordpress.org/core/2023/11/13/wordpress-6-4-performance-improvements/ - WordPress 6.4 Field Guide: https://make.wordpress.org/core/tag/6-4/ - Dev notes index (performance): https://make.wordpress.org/core/tag/performance/ - GitHub Action for benchmarking: https://github.com/WordPress/wordpress-develop/tree/trunk/.github/actions/compare-wp-performance ## 🗣️ Paraphrase: - Original idea: “WordPress 6.4 improves server response by ~4% vs 6.3.2, with frontend optimizations that improve LCP—~4% on Twenty Twenty-One and ~9% on Twenty Twenty-Three.” - Paraphrase: Compared to 6.3.2, WordPress 6.4 trims server response times by roughly four percent. Combined with front-end tuning, that yields better LCP metrics—around four percent faster on the Twenty Twenty-One theme and about nine percent on Twenty Twenty-Three. - Original idea: “This release evolves benchmarking by automating tests via a GitHub Action that builds two standard sites, runs 100 requests, repeats five times, and reports median metrics.” - Paraphrase: The team standardized performance testing by shifting to an automated GitHub Action. It provisions two identical test sites, executes one hundred requests per run, repeats the process five times, and publishes median values for dependable comparisons. ## 📰 Newsletter: WordPress 6.4 lands with real-world speed boosts you can feel. We’re seeing roughly 4% faster server responses compared to 6.3.2 and notably better LCP—about 4% with Twenty Twenty-One and 9% with Twenty Twenty-Three. Under the hood: smarter object caching, refined options functions, tighter template loading, and leaner image/script handling (plus cleaner inline styles). Bonus: the performance team rolled out reproducible benchmarking using a standardized GitHub Action—so the numbers aren’t just fast, they’re trustworthy. Dive deeper in the WordPress 6.4 Field Guide and the performance post for all the nerdy bits and bobs. Links: - WordPress 6.4 performance summary: https://make.wordpress.org/core/2023/11/13/wordpress-6-4-performance-improvements/ - WordPress 6.4 Field Guide: https://make.wordpress.org/core/tag/6-4/ Learning web dev? Peek at how small changes to caching, script strategy, and image loading move the Core Web Vitals needle—great lessons for your next project. Community shoutouts to the Performance Team for pushing both speed and testing rigor. New plugin releases? Keep an eye on caching helpers and image optimizers—pairing them with 6.4 is like coffee plus a fresh SSD. ## ✅ Action Items: Prompt for alignment with your Developer Advocate/OSPO goals: “Analyze how this article demonstrates open-source performance stewardship in WordPress 6.4. Map each improvement (object caching, options API, template loading, image/script optimizations) to: - Open-source advocacy: How does transparent benchmarking (GitHub Action, wp-env) and public dev notes model best practices for OSS projects? - Contributor engagement: What on-ramps exist for new contributors (e.g., performance team calls, reproducible CI workflows)? Propose a contributor journey from ‘good-first-issue’ to benchmarking maintainer. - Education: Translate each performance change into teachable modules for PHP, JS, HTML, CSS, Git/GitHub curricula. Include code labs on optimizing LCP, measuring server timing, and writing benchmarkable patches. - Sustainable funding: Identify areas where sponsorship accelerates reproducible testing, infrastructure, and long-term maintenance of performance tooling. - OSPO objectives: Extract policies/processes an OSPO could standardize (CI benchmarks, performance budgets, documentation templates, release checklists) to scale across product teams. - Transparency & inclusivity: Suggest practices to ensure - Summary: WordPress 6.4 is the latest release that focuses on improving the performance of the core software. It includes server-side and client-side optimizations that result in a 4% improvement in server response time compared to the previous version. These improvements also contribute to better Largest Contentful Paint (LCP) scores, with a 4% improvement for Twenty Twenty-One theme and a 9% improvement for Twenty Twenty-Three theme. The Performance Team has worked tirelessly throughout the year to enhance performance, and you can find more information about the specific improvements in the release notes. The team has also refined their benchmarking methodology to ensure reproducibility and accuracy in performance measurements. However, there is still room for further improvements in future releases. - URL: https://make.wordpress.org/core/2023/11/13/wordpress-6-4-performance-improvements/ WordPress 6.4 is the third major release of the year that delivers a better user experience to site visitors by improving performance of the core software. **This version improves server response time by ~4% over version 6.3.2**. This, combined with additional frontend optimizations, leads to improvements to Largest Contentful Paint (LCP)—an important Core Web Vital. For example, Twenty Twenty-One (a classic theme) shows an improvement of ~4% for LCP and Twenty Twenty-Three (a block theme) shows a ~9% LCP improvement when run on WordPress 6.4 compared with 6.3.2 based on benchmarks conducted by the WordPress Performance team. This release caps off an ambitious year of work for the Performance Team, with major improvements made in each release. You can read more about those improvements in the performance improvement summary posts for [version 6.2](https://make.wordpress.org/core/2023/04/05/wordpress-6-2-performance-improvements-for-all-themes/) and [version 6.3](https://make.wordpress.org/core/2023/08/07/wordpress-6-3-performance-improvements/). While version 6.2 focused on server side improvements, and 6.3 focused more on client side improvements, this release was focused on continuing server side improvements while further optimizing and extending the improvements that were made earlier in the year. Meanwhile, the team continued iterating on the tools and methodologies used to measure and report on performance. #### Performance highlights for this release An overview of the performance enhancements in this release is included in the [WordPress 6.4 Field Guide](https://make.wordpress.org/core/2023/10/23/wordpress-6-4-field-guide/) and you can read details about the following highlights in their individual dev-note posts: **Server side improvements** **Client side improvements** #### Evolving our benchmarking methodology Previous performance benchmarks reported for each release were taken by [@flixos90](https://profiles.wordpress.org/flixos90/) (the performance release lead) on his own computer, using a standardized set of [best practices and tools](https://make.wordpress.org/performance/handbook/measuring-performance/best-practices-for-performance-measurement/). This release we have attempted to automate the process in order to establish a reproducible methodology that can be used by any contributor using a standard set of tools. The process for this release uses the [compare-wp-performance](https://github.com/swissspidy/compare-wp-performance) GitHub action, originally developed by [@swissspidy](https://profiles.wordpress.org/swissspidy/), which sets up two standard test sites using [wp-env](https://developer.wordpress.org/block-editor/reference-guides/packages/packages-env/) inside of a GitHub worker, takes a set of metrics based on 100 requests, and reports them in the action summary ([example](https://github.com/joemcgill/compare-wp-performance/actions/runs/6789622397)). To account for variance between each run, this is done 5 times and the median values are used for reporting purposes. ##### Revisiting previous releases Since the testing environment has an important impact on performance benchmarks, we wanted to revisit the previous versions from this year and apply the same methodology for comparison. Each of the following metrics show the percentage the metric either improved (negative numbers) or got worse (positive numbers) between versions. **Twenty Twenty-One** * LCP: +2.87% * Server Timing -4.21% **Twenty Twenty-Three** * LCP: -4.72% * Server Timing -18.15% **Twenty Twenty-One** * LCP: -10.82% * Server Timing -3.34% **Twenty Twenty-Three** * LCP: -14.23% * Server Timing -10.21% **Twenty Twenty-One** * LCP: -3.95% * Server Timing -4.05% **Twenty Twenty-Three** * LCP: -9.06% * Server Timing -4.59% Detailed data can be found in [this spreadsheet](https://docs.google.com/spreadsheets/d/1WQWDogvzPzof9VJiDAviB12lM_lbETlAljOufZrvcFs/edit#gid=832647379), with links to the individual GitHub workflows. ##### Future improvements While the methodology used for this release is an improvement over the previous process, there is much room for improvement, including finding ways to [stabilize the metrics](https://github.com/WordPress/performance/issues/849) collected during benchmarks for releases and during development, improving the test content and use cases we test for these benchmarks, testing different configurations and environment characteristics (e.g., PHP versions, persistent object cache, etc.). #### Props Props to [@joemcgill](https://profiles.wordpress.org/joemcgill/) for taking the time to write this extensive and detailed post, and [@flixos90](https://profiles.wordpress.org/flixos90/) for review., WordPress 6.4 Performance Improvements, Emily Clarke, 01hf725twypg0ct145reass56q.