Here’s a practical, step-by-step PrestaShop Speed Optimisation Guide that works very well for PrestaShop 8 & 9 (shared hosting → VPS).
I’ve ordered this from maximum impact → advanced tuning.

🚀 PrestaShop Speed Optimisation Guide

1️⃣ Hosting & Server (Biggest Speed Factor)

✅ Choose the Right Hosting

Minimum recommended:

• SSD / NVMe storage
• PHP 8.1 or 8.2
• Memory: 2 GB RAM (4 GB ideal)
• Web server: LiteSpeed or Nginx (faster than Apache)

👉 If possible, use:

• LiteSpeed + LSCache
• OR Nginx + Redis

✅ PHP Settings (Very Important)

Set these in cPanel → PHP INI Editor or .user.ini:

memory_limit = 512M
max_execution_time = 300
max_input_vars = 5000
upload_max_filesize = 64M
post_max_size = 64M

Enable:

• opcache
• intl
• zip

2️⃣ Enable PrestaShop Performance Settings

Go to:

Back Office → Advanced Parameters → Performance

🔹 Smarty Settings

✔ Template compilation → Recompile templates if files have been updated
✔ Cache → Yes
✔ Clear cache → After changes only

🔹 Debug Mode

❌ Turn OFF (very important for speed)

🔹 CCC (Combine, Compress, Cache)

Enable all:

✔ Smart cache for CSS
✔ Smart cache for JavaScript
✔ Minify HTML
✔ Compress inline JS
✔ Compress inline CSS
✔ Move JavaScript to the end
✔ Apache optimization (if Apache)

📌 Clear cache after enabling.

3️⃣ Image Optimisation (Huge Speed Gain)

✅ Resize & Compress Images

• Use WebP images if possible
• Re-generate thumbnails:
  • Design → Image Settings → Regenerate thumbnails

✅ Recommended Image Sizes

Avoid unnecessary sizes:

• Keep only sizes used by your theme
• Delete unused image types

✅ Image Compression Tools

• TinyPNG
• ImageOptim
• ShortPixel (module)

4️⃣ Theme Optimisation

❌ Avoid Heavy Themes

Problems with:

• Too many animations
• Built-in sliders
• Multiple JS libraries

✅ Recommended

• Lightweight themes
• Minimal homepage blocks

📌 Disable unused theme features.

5️⃣ Modules Cleanup (Critical)

❌ Remove Unused Modules

Go to:
Modules → Module Manager

Disable or uninstall:

• Statistics modules
• Unused payment gateways
• Old SEO modules
• Demo / sample modules

📌 Each active module adds database & JS load.

6️⃣ Database Optimisation

✅ Clean Database

Remove:

• Old carts
• Old connections
• Logs
• Search index (rebuild later)

Recommended modules:

• Database Cleaner (official)

✅ Optimize Tables

Via phpMyAdmin:

• Select all tables
• Click Optimize table

7️⃣ Enable Caching (Advanced)

🔹 Redis Cache (Best)

If your host supports Redis:

Advanced Parameters → Performance

• Cache system → Redis
• Enter Redis server details

⚡ Big speed improvement on category & product pages.

🔹 File System Cache (Basic Hosting)

If Redis not available:

• Enable File system cache

8️⃣ Use CDN (Cloudflare – Free)

✅ Cloudflare Setup

• Enable Auto Minify (HTML, CSS, JS)
• Enable Brotli
• Enable Caching
• Turn on HTTP/2 & HTTP/3

📌 Cloudflare alone can reduce load time by 30–50%.

9️⃣ Enable GZIP / Brotli Compression

Check .htaccess:

<IfModule mod_deflate.c>
  AddOutputFilterByType DEFLATE text/html text/css text/javascript application/javascript
</IfModule>

📌 Cloudflare does this automatically.

🔟 Reduce External Requests

Avoid:

• Too many Google Fonts
• Multiple analytics scripts
• Heavy chat widgets

Combine:

• Google Fonts into 1 request
• Load scripts after page load

1️⃣1️⃣ Lazy Load Images

Enable:

• Image lazy loading
• Iframe lazy loading

Most modern themes support this by default.

1️⃣2️⃣ Speed Testing Tools

Test before & after changes:

• Google PageSpeed Insights
• GTmetrix
• WebPageTest

📌 Focus on:

• LCP
• CLS
• TTFB

⚠️ Common Speed Mistakes

❌ Debug mode ON
❌ Too many modules
❌ Uncompressed images
❌ Heavy homepage sliders
❌ Cheap shared hosting

✅ Ideal Speed Setup (Best Practice)

✔ LiteSpeed + LSCache
✔ Redis cache
✔ Cloudflare CDN
✔ WebP images
✔ Minimal theme
✔ CCC enabled
✔ Unused modules removed