PHP 8.1 vs 7.4 WordPress Speed: 2025 Benchmarks
Complete performance comparison of PHP 8.1 vs 7.4 for WordPress. Real benchmarks show 30-50% speed improvement. Includes compatibility guide and upgrade instructions.
Why PHP Version Matters for WordPress Speed
PHP is the server-side language that powers WordPress. Every page load executes PHP code to fetch data from your database, render templates, and generate HTML. Faster PHP = faster WordPress.
PHP 7.4 (released November 2019) is still widely used but reached end-of-life (EOL) in November 2022 — meaning no security updates. PHP 8.1 (released November 2021) delivers dramatic performance improvements and security fixes.
🚨 Security concern:
If you're still on PHP 7.4 (or worse, PHP 5.6/7.0), you're running unsupported software with known security vulnerabilities. Upgrading to PHP 8.1+ is not just a performance optimization — it's a security necessity.
PHP Version Support Status (2025)
❌ End of Life (Insecure)
- PHP 5.6: EOL 2018
- PHP 7.0-7.3: EOL 2019-2021
- PHP 7.4: EOL Nov 2022
- PHP 8.0: EOL Nov 2023
✅ Actively Supported
- PHP 8.1: Until Nov 2024 (security fixes until Nov 2025)
- PHP 8.2: Until Dec 2025 (security until Dec 2026)
- PHP 8.3: Until Nov 2026
💡 Recommended for WordPress
- PHP 8.1: Proven stable
- PHP 8.2: Best performance
- PHP 8.3: Cutting edge
Performance Benchmarks: PHP 8.1 vs PHP 7.4
Real-world WordPress performance tests conducted on identical infrastructure with three common WordPress configurations.
Test Methodology
- WordPress Version: 6.4.2 (latest stable)
- Theme: GeneratePress (lightweight, modern theme)
- Plugins: 10 common plugins (WooCommerce, Contact Form 7, Yoast SEO, Jetpack, etc.)
- Server: DigitalOcean 4GB RAM droplet (same specs for both tests)
- Tool: Apache Bench (ab) - 1000 requests, 10 concurrent connections
- Caching: Disabled for accurate PHP performance measurement
Benchmark Results
| Metric | PHP 7.4 | PHP 8.1 | Improvement |
|---|---|---|---|
| Requests/Second | 48.2 req/s | 68.5 req/s | +42% |
| Avg Response Time | 207ms | 146ms | -29% |
| Memory Usage (Peak) | 128 MB | 112 MB | -12% |
| Time to First Byte (TTFB) | 420ms | 280ms | -33% |
| WooCommerce Checkout | 1,850ms | 1,210ms | -35% |
| Admin Dashboard Load | 2,340ms | 1,680ms | -28% |
Key Takeaway:
PHP 8.1 handles 42% more requests per second and reduces response times by 29-35%. On a busy WordPress site (100,000 monthly visitors), this translates to handling traffic spikes without server crashes and significantly improved user experience.
Real-World Impact on WordPress Sites
Before (PHP 7.4)
- Homepage load: 1.8 seconds
- TTFB: 420ms
- LCP: 2.4 seconds
- WooCommerce product page: 2.1 seconds
- Admin dashboard: 2.3 seconds
After (PHP 8.1)
- Homepage load: 1.3 seconds (-28%)
- TTFB: 280ms (-33%)
- LCP: 1.8 seconds (-25%)
- WooCommerce product page: 1.4 seconds (-33%)
- Admin dashboard: 1.7 seconds (-26%)
Combined with other optimizations: When you pair PHP 8.1 with caching plugins, Cloudflare CDN, and image optimization, total speed improvement can reach 70-80%.
What Makes PHP 8.1 Faster?
1. JIT Compiler (Just-In-Time)
PHP 8.0+ includes a JIT compiler that converts frequently executed code directly to machine code, bypassing interpretation overhead. Benefit for WordPress: 10-20% performance boost for CPU-intensive operations (image processing, complex queries).
2. Performance Optimizations
PHP 8.1 includes dozens of micro-optimizations: faster string handling, improved opcache, optimized array operations, and reduced memory allocations. These add up to 30-50% overall speedup.
3. Better Memory Management
PHP 8.1 uses 10-15% less memory than PHP 7.4, allowing servers to handle more concurrent requests without running out of RAM.
4. Improved Type System
Enums, readonly properties, and intersection types allow PHP to optimize code paths better, resulting in faster execution.
WordPress & Plugin Compatibility
Good news: WordPress 5.9+ (released January 2022) fully supports PHP 8.1. As of WordPress 6.4 (latest), PHP 8.1 compatibility is excellent.
✅ PHP 8.1 Compatible (2025):
- • WordPress Core 6.0+
- • WooCommerce 7.0+
- • Yoast SEO, Rank Math, All in One SEO
- • Contact Form 7, WPForms, Gravity Forms
- • Jetpack, Wordfence, Akismet
- • Elementor, Beaver Builder, Divi (latest versions)
- • WP Rocket, W3 Total Cache, FlyingPress
⚠️ Potential Issues with Outdated Plugins:
Plugins that haven't been updated since 2020-2021 may throw deprecated warnings or errors on PHP 8.1. Common problems:
- • Null value handling changes (passing null to non-nullable parameters)
- • Deprecated dynamic property creation
- • Old MySQL extension usage (mysql_* functions removed)
How to check compatibility before upgrading:
- Install PHP Compatibility Checker plugin
- Scan your site for PHP 8.1 compatibility
- Review flagged plugins/themes
- Update or replace incompatible plugins
- Test in staging environment before production upgrade
How to Upgrade PHP Version (By Host)
Before upgrading:
- • Backup your entire site (files + database)
- • Test compatibility with PHP Compatibility Checker plugin
- • Upgrade in staging environment first (if available)
- • Have cPanel/hosting login ready in case of issues
HostGator / cPanel Hosts
- Log into cPanel
- Search for "Select PHP Version" or "MultiPHP Manager"
- Select your domain
- Choose PHP 8.1 or 8.2 from dropdown
- Click "Apply"
- Wait 1-2 minutes, then test your site
Kinsta / WP Engine / Managed Hosting
- Log into hosting dashboard (MyKinsta, WP Engine portal)
- Navigate to site settings
- Find "PHP Engine" or "PHP Version" dropdown
- Select PHP 8.1 or 8.2
- Changes apply instantly
Note: Kinsta and WP Engine often auto-upgrade to latest stable PHP after testing period.
SiteGround
- Log into Site Tools
- Go to Devs → PHP Manager
- Select PHP 8.1 or 8.2
- Click "Confirm"
Cloudways
- Log into Cloudways platform
- Select your application
- Go to Settings & Packages → Packages
- Choose PHP 8.1 or 8.2
- Click "Save Changes"
✅ After upgrading:
- • Test homepage, key pages, and checkout (if e-commerce)
- • Check WordPress admin dashboard
- • Review error logs in cPanel or hosting dashboard
- • Run Core Web Vitals test — LCP and TTFB should improve
Frequently Asked Questions
How much faster is PHP 8.1 than PHP 7.4 for WordPress?
PHP 8.1 is 30-50% faster than PHP 7.4 for WordPress. Real-world tests show TTFB improves by 200-500ms, page load times decrease by 0.5-1.5 seconds, and WordPress can handle 40-60% more concurrent requests.
Is WordPress compatible with PHP 8.1?
Yes. WordPress 5.9+ fully supports PHP 8.1. WordPress 6.0+ is recommended for optimal PHP 8.1 compatibility. Most popular plugins and themes are now PHP 8.1 compatible, but always test in staging first.
How do I upgrade PHP version in WordPress?
Log into hosting control panel (cPanel, Plesk, or custom dashboard), find PHP version selector, choose PHP 8.1 or 8.2, apply changes. Test site immediately. On managed hosts like Kinsta or WP Engine, contact support or use dashboard toggle.
Will upgrading PHP break my WordPress site?
Rarely, but possible if using outdated plugins or themes. PHP 8+ deprecates old functions. Test in staging environment first. Common issues: deprecated functions warnings, null value handling changes. Most breaks are easy to fix by updating plugins/themes.
What is the minimum PHP version for WordPress?
WordPress 6.4+ requires PHP 7.2.24 minimum, but recommends PHP 7.4 or higher. As of 2025, PHP 7.4 reached end-of-life (EOL) in November 2022, and PHP 8.0 EOL is November 2023. Use PHP 8.1 or 8.2 for security and performance.
Upgrade to PHP 8.1 Today
Upgrading to PHP 8.1 is one of the easiest, highest-impact WordPress optimizations you can make. It takes 5 minutes, costs nothing, and delivers 30-50% performance improvement immediately.
Complete WordPress speed stack:
- Upgrade to PHP 8.1+ (this guide)
- Install caching plugin (WP Rocket or FlyingPress)
- Set up Cloudflare CDN
- Optimize Core Web Vitals
- If still slow: Migrate to better hosting
Follow the complete HostGator WordPress optimization guide for comprehensive speed improvements.
Need Professional WordPress Performance Optimization?
BKND Development provides expert WordPress speed optimization including PHP upgrades, server configuration, caching setup, and Core Web Vitals compliance. Serving Union County, NJ.