Performance Feb 27, 2026 7 min read

Why Your Website Feels Slow (And How to Actually Fix It)

Your site's slow loading time usually comes from a stack of fixable problems. Here's how to find them, measure them, and fix them in the right order.

Your homepage loads in 4.2 seconds. You've heard that's bad, but you're not sure where to start fixing it. You run a speed test, get a score of 58, and stare at a list of recommendations that reads like a foreign language.

You're not alone. Most site owners know their site is slow. Few know exactly why, or what to do about it in the right order. This post walks you through the real causes of slow websites and the specific techniques that move the needle.

Start With Measurement, Not Guessing

Before touching a single file, measure. You need real data, not instinct.

Use these tools to get a clear picture:

Google PageSpeed Insights — gives you Core Web Vitals scores from real Chrome users plus lab data
GTmetrix — shows a waterfall of every resource your page loads and how long each takes
WebPageTest — lets you test from specific locations and connection types
Lighthouse — built into Chrome DevTools, great for iterating locally

Run tests from multiple locations. A site that loads in 1.2 seconds in Tel Aviv might take 3.8 seconds in Los Angeles if your server is in Europe with no CDN in front of it.

Understanding Core Web Vitals

Google uses three Core Web Vitals as ranking signals. These aren't vanity metrics — they directly reflect how your visitors experience your site.

Largest Contentful Paint (LCP)

LCP measures how long it takes for the largest visible element to load. That's usually a hero image, a large heading, or a video thumbnail. Your target is under 2.5 seconds.

The biggest LCP killers:

Unoptimized hero images (a 2MB JPEG is a death sentence)
Render-blocking CSS or JavaScript above the fold
Slow server response times (TTFB over 600ms)
No CDN serving assets close to the user

Interaction to Next Paint (INP)

INP replaced First Input Delay and measures the full latency of user interactions — clicks, taps, keyboard input. Target: under 200ms. Long JavaScript tasks on the main thread are the primary culprit here.

Cumulative Layout Shift (CLS)

CLS scores how much your page jumps around as it loads. A score above 0.1 means something is shifting — usually images without defined dimensions, or fonts swapping in late. Target: under 0.1.

Fix CLS by always setting explicit width and height attributes on images, and using font-display: optional or font-display: swap carefully.

Image Optimization: The Biggest Win You're Probably Missing

Images typically account for 50–70% of a page's total weight. This is where most sites have the most room to improve.

Use Modern Formats

WebP delivers roughly 25–35% smaller file sizes than JPEG at equivalent quality. AVIF goes even further — 50% smaller than JPEG in many cases. Serve them with a fallback:

Lazy Load Below-the-Fold Images

Don't load images the user can't see yet. The native loading="lazy" attribute works in all modern browsers and requires zero JavaScript:

Never lazy load your LCP image. That will hurt your score, not help it.

Compress Without Destroying Quality

Tools like Squoosh, Sharp (for Node.js pipelines), and Imagick (for PHP) let you compress aggressively while keeping visual quality high. Aim for 80–85% quality on JPEG/WebP. Most users can't tell the difference, but the file size difference is dramatic.

Caching: The Strategy That Multiplies Every Other Optimization

Caching means storing a copy of something so you don't have to regenerate or re-fetch it. Done right, it's the single highest-leverage performance technique.

Server-Side Caching

For WordPress and PHP-based sites, full-page caching stores the rendered HTML so PHP and MySQL don't run on every request. Tools like Redis Object Cache store database query results in memory, so repeat lookups take microseconds instead of milliseconds.

At Proginter, server-side caching is built into the panel. You can enable it with one click and see Time to First Byte drop from 800ms to under 100ms on cached pages.

Browser Caching

Tell browsers to hold onto static assets — images, CSS, fonts, JavaScript — so returning visitors don't re-download them. Set it via HTTP headers:

Cache-Control: public, max-age=31536000, immutable

Use that for versioned assets (anything with a hash in the filename). For HTML, use shorter cache times or no-cache so changes appear immediately.

CDN Caching

A Content Delivery Network stores copies of your static assets at edge nodes around the world. A user in São Paulo gets your images from a server in Brazil, not your origin server in Frankfurt. Latency drops from 180ms to 12ms for that asset.

CDNs are non-negotiable if you have international traffic. Most managed hosting providers, including Proginter, include CDN integration in their plans.

PHP and Database Performance

Slow server response time is often a PHP or database problem, not a network problem.

PHP Performance

A few quick wins that have a real impact:

Enable OPcache — PHP compiles scripts to bytecode and stores them in memory. This alone can cut PHP execution time by 40–60%.
Use PHP 8.2 or later — Each major version brings meaningful speed improvements. PHP 8.x is significantly faster than 7.x.
Avoid unnecessary plugins — In WordPress, every active plugin adds PHP execution overhead. Audit your plugins regularly.

Database Query Optimization

A single unindexed query on a large table can add hundreds of milliseconds to a page load. Use the slow query log to find the worst offenders:

SET GLOBAL slow_query_log = 'ON'; SET GLOBAL long_query_time = 1;

Then add indexes on columns you frequently filter or sort by. In WordPress, the wp_postmeta table is a common bottleneck — make sure meta_key is indexed, which it is by default, but custom queries against it often aren't.

The Infrastructure Layer: NVMe Storage and Server Resources

Software optimizations matter less when the hardware underneath is slow. NVMe SSDs read and write data 5–7x faster than traditional SATA SSDs. For database-heavy sites, this directly translates to faster query execution and lower TTFB.

Monitor your server's resource usage with tools like htop, Netdata, or your hosting panel's built-in metrics. Watch for:

CPU usage consistently above 70% — you may need to optimize or scale
Memory usage approaching limits — PHP-FPM workers will start queuing requests
Disk I/O wait times above 5% — a sign queries or file operations are bottlenecking

Load Testing Before You Need It

Don't wait for a traffic spike to find out your server buckles under load. Test it first.

k6 and Locust are excellent open-source tools for simulating concurrent users. A basic k6 test that ramps to 200 virtual users over 30 seconds takes about 10 lines of JavaScript and will tell you exactly where your site breaks.

Run load tests on your staging environment, not production. At Proginter, every plan includes a staging environment for exactly this reason.

Putting It Together

Web performance isn't one thing you fix — it's a stack of decisions that compound. The order matters:

Measure first. Know your baseline.
Fix TTFB — server caching, PHP optimization, NVMe storage.
Optimize images — format, compression, dimensions, lazy loading.
Set up CDN and browser caching.
Address Core Web Vitals issues specifically — LCP, INP, CLS each have distinct fixes.
Load test before major traffic events.

Each step builds on the last. A fast server with unoptimized images is still slow. Perfect images on a slow server are still slow. Work through the stack systematically and you'll see scores and real-world load times improve together.

If you're on Proginter, start in the panel — smart caching, CDN, and performance monitoring are already there. The AI assistant Proper can also walk you through specific fixes based on your site's actual configuration.