Diagnosing Slow Site Performance

If your site has gotten slower over time, the cause is almost always one of: too many plugins, unoptimised images, missing caching, or a database that needs maintenance. Here is how to find the culprit.

1. Measure first

Run your site through:

• PageSpeed Insights — Google's official measurement, with mobile and desktop scores.
• GTmetrix — waterfall view of every request and its timing.
• WebPageTest — real-browser tests from multiple regions.

Note your current numbers before making changes — otherwise you cannot tell what helped.

2. Optimise images

Images are usually the largest single category of bytes. Quick wins:

• Compress JPEGs and PNGs (use Squoosh for one-offs, an image plugin for bulk).
• Serve modern formats (WebP, AVIF).
• Resize before upload — never upload a 4000px image to display at 600px.
• Add loading="lazy" to below-the-fold images.

3. Enable caching

• Page caching — turns dynamic page renders into static HTML for repeat visitors. WordPress plugins: WP Rocket, W3 Total Cache, LiteSpeed Cache.
• Browser caching — set far-future Cache-Control headers on static assets.
• Object caching — Redis or Memcached for database query results (available on most VPS plans).

4. Trim plugins and themes

Disable plugins one at a time and re-test. Plugins that hook into every request (analytics, security, related-posts) are common offenders. If a plugin is essential but slow, look for a lighter alternative.

5. Check your database

Open phpMyAdmin and look at your largest tables — old logs, transient cache rows, spam comments, and post revisions can balloon a database. WordPress users: tools like WP-Optimize clean these up safely.

6. Consider a CDN

A CDN (Cloudflare, Bunny, Fastly) caches your static assets at edge locations close to your visitors. The free Cloudflare plan delivers a meaningful speed boost on most sites in 15 minutes of setup.

7. When the server is the bottleneck

If you have done all of the above and PageSpeed still flags Server response time as slow, the issue is the underlying plan. Consider upgrading to a higher shared plan or moving to a VPS — see our blog post Shared Hosting vs VPS.