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WordPress 6.4 Performance Tips: 12 Wins You Can Ship This Week

WordPress 6.4 Performance Tips: 12 Wins You Can Ship This Week

12 specific, ship-this-week wins for WordPress 6.4+ performance. Across 200+ WordPress audits, these are the fixes that consistently move Core Web Vitals fastest.

Sorted by impact-to-effort ratio. Start at the top, ship one fix per day, and you''ll have measurable CWV gains within two weeks.

Image and asset wins

1. Convert to AVIF (with WebP fallback)

Modern format that''s 30-50% smaller than WebP. Most CDNs (Cloudflare, BunnyCDN) auto-serve AVIF when supported. This is the single biggest LCP win for image-heavy sites.

2. Set explicit width and height on images

Stops layout shift on lazy-load. WordPress 6.4+ does this automatically for new uploads — but legacy images need a backfill. Use a plugin like ShortPixel or hand-update.

3. Preload your LCP image

Add <link rel="preload" as="image" href="..."> in <head> for the hero. Saves 200-400ms of LCP on most sites.

4. Self-host fonts with subsetting

Google Fonts CDN is slower than your own host in 2026. Subset to only the characters you use, self-host with font-display: swap. Often 300-500ms LCP saving.

JavaScript wins

5. Defer non-critical scripts

Chat widgets, analytics, email capture popups — defer all of them. Add defer attribute or load via requestIdleCallback.

6. Audit your plugin JS bundle

Most plugins ship CSS/JS on every page even when not needed. Use a tool like Asset CleanUp or Perfmatters to dequeue assets per page.

7. Replace heavy plugins

Slider Revolution, WPBakery — both add 200-500kb of JS per page. Replace with native blocks or lighter alternatives.

Caching and infrastructure

8. Page caching with WP Rocket or LiteSpeed Cache

Non-negotiable. Reduces TTFB from 800ms to under 100ms on most sites. Combined with object caching it''s transformative.

9. Object caching (Redis or Memcached)

Caches database query results. Most managed WP hosts (Kinsta, Cloudways) offer this — turn it on. 30-50% faster admin and front-end.

10. Use a CDN — properly

Cloudflare, BunnyCDN, KeyCDN. Make sure full-page caching is enabled for anonymous traffic. APO for Cloudflare or BunnyCDN with full-page caching is dramatic.

WordPress core wins

11. Disable embed.js if you don''t use embeds

WordPress loads embed.js on every page. If you don''t need oEmbed, dequeue it.

12. Reduce REST API surface

Disable REST API on the public frontend if you don''t need it. Reduces attack surface and load time. Use plugins like Disable REST API Endpoints.

What NOT to do

  • Don''t install 5 caching plugins. They conflict. One good one is enough.
  • Don''t lazy-load above-the-fold images. It hurts LCP. Lazy-load only below the fold.
  • Don''t inline all your CSS. Inline only critical CSS (above-the-fold). The rest should be cached.

Key Takeaways

  • Image format (AVIF), font hosting, and JS deferral are the highest-impact wins.
  • Page + object caching is non-negotiable for any serious WordPress site.
  • Plugin audits — most sites have 30-50 plugins, half are dead weight.
  • Ship one fix per day and you''ll see meaningful CWV improvement within two weeks.
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