westonruter

twentyten

npm run research -- benchmark-web-vitals --url=http://wp68.local/block-category-common/ --url=http://wp69.local/block-category-common/ --number=100 --network-conditions=broadband --diff --output=md

URL	http://wp68.local/block-category-common/	http://wp69.local/block-category-common/	Diff (ms)	Diff (%)
Success Rate	100%	100%	--	--
FCP (median)	194.75	181.15	-13.60	-7.0%
LCP (median)	300.4	294.9	-5.50	-1.8%
TTFB (median)	34.4	36.7	+2.30	+6.7%

westonruter

twentyten

npm run research -- benchmark-web-vitals --url=http://wp68.local/sample-page/ --url=http://wp69.local/sample-page/ --number=100 --network-conditions=broadband --diff --output=md

URL	http://wp68.local/sample-page/	http://wp69.local/sample-page/	Diff (ms)	Diff (%)
Success Rate	100%	100%	--	--
FCP (median)	170.3	161	-9.30	-5.5%
LCP (median)	201.1	191.1	-10.00	-5.0%
TTFB (median)	29.9	33.6	+3.70	+12.4%

westonruter

👉 Dev note published: WordPress 6.9 Frontend Performance Field Guide

---

I'm working on a Dev Note which will detail all of the performance improvements in WordPress 6.9. See full list in Trac. In the mean time, here are a couple outlines:

Links below either point to a specific ticket or a Trac query for the group of tickets:

4-bullet highlights

westonruter

The two sites are running on LocalWP with PHP 8.2, MySQL 8, Nginx. They both have the theme unit test data installed. The Twenty Twenty-One theme is active. In the Customizer, the theme is configured to show full content instead of excerpts on archive pages.

benchmark-server-timing on Sample Page

npm run research -- benchmark-server-timing --url=http://wp68.local/sample-page/ --url=http://wp69beta4.local/sample-page/ --number=100 --diff --output=md

URL	http://wp68.local/sample-page/	http://wp69beta4.local/sample-page/	Diff (ms)	Diff (%)

westonruter

The two sites are running on LocalWP with PHP 8.2, MySQL 8, Nginx. They both have the theme unit test data installed. The Twenty Twenty-Five theme is active.

benchmark-server-timing on Sample Page

npm run research -- benchmark-server-timing --url=http://wp68.local/sample-page/ --url=http://wp69beta4.local/sample-page/ --number=100 --diff --output=md

URL	http://wp68.local/sample-page/	http://wp69beta4.local/sample-page/	Diff (ms)	Diff (%)

westonruter

--- 68-sample-page-without-theme-support.html	2025-10-28 17:56:40
+++ 68-sample-page-with-theme-support.html	2025-10-28 17:56:40
@@ -521,6 +521,179 @@
       href="http://localhost:8000/wp-includes/css/dist/block-library/style.css?ver=6.8.3-src"
       media="all"
     />
+    <style id="wp-block-library-theme-inline-css">
+      .wp-block-audio :where(figcaption) {
+        color: #555;
+        font-size: 13px;

westonruter

<?php
/**
 * Plugin Name: Try Featured Image as OG Image
 */

function apply_wp_content_img_tag_filters( string $markup, int $attachment_id ): string {
	return apply_filters( 'wp_content_img_tag', $markup, '', $attachment_id );
}

add_action(

westonruter

As of 6.9-beta1:

Size (Bytes)	File Path
19126	./cover/style.min.css
16879	./navigation/style.min.css
16120	./gallery/style.min.css
11762	./social-links/style.min.css
6758	./image/style.min.css
3888	./table/style.min.css

westonruter

#!/bin/bash

# =============================================================================
#
# WordPress Theme Performance Benchmarking Script
#
# This script automates the process of benchmarking the performance impact of a
# change across multiple WordPress themes. It activates each theme, runs
# Lighthouse multiple times for a "before" and "after" URL, calculates the
# median performance score, and outputs the results in a Markdown table.

westonruter

<?php
/**
 * Plugin Name: Active Plugins Override
 * Description: Install this as an mu-plugin to override the active plugins via query parameters.
 * Plugin URI: https://gist.github.com/westonruter/9c791f4f8cc1cc37e7b3f4bc2db9be97
 * Requires PHP: 7.2
 * Version: 0.1.0
 * Author: WordPress Performance Team
 * Author URI: https://make.wordpress.org/performance/
 * License: GPLv2 or later