Case Study: How We Cut Load Time 55% And Boosted Leads 15%
Data-backed optimizations slashed LCP from 4.2s to 1.9s and improved CLS from 0.28 to 0.05, driving a 15% lift in lead submissions.
A deep dive into the data‑backed optimizations that transformed a client's website from “good enough” to a high‑performance conversion engine.
The Problem: A Great‑Looking Website That Wasn't Growing the Business
Our client, AI Vibe, had everything you’d want in a website: a sharp design, great features, and a steady stream of visitors. But growth had flatlined. Despite good traffic, new customer leads weren’t increasing.
The website looked good, but it felt slow and clunky. This subtle friction was an invisible tax on the business, costing customers every single day.
This “feeling” has a name: Core Web Vitals — Google’s official report card for user experience that impacts rankings and revenue.
The Diagnosis: Finding the Bottlenecks with Data
We ran a full diagnostic using Google’s tools to get an objective report card for real users. Results were clear.
The "Before" Scores
- Load Time (LCP): 4.2 seconds — Poor
Meaning: The most important content took over 4 seconds to appear. Many visitors leave after ~3 seconds. What is LCP? - Visual Stability (CLS): 0.28 — Poor
Meaning: The layout jumped while loading, causing mis‑clicks and eroding trust. What is CLS?
Root causes:
- A massive, unoptimized hero image.
- Images/ads loading without reserved space.
- A heavy contact form loading all at once.
The Fix: A Three‑Pronged Optimization Strategy
Fixing a slow website isn’t about one magic bullet; it’s about intelligently managing how resources load.
Fix #1: Conquering Slow Load Times with a Smart Image Strategy
- Smarter formats: Convert to WebP and generate mobile‑specific versions.
- Prioritization: Mark the hero as highest priority so it loads first.
- Lazy loading: Defer off‑screen images until scrolled into view.
Fix #2: Eliminating the "Jumpy" Layout by Reserving Space
Add explicit width/height to images and containers to reserve space before they load — a simple, high‑impact way to prevent layout shifts (CLS).
Fix #3: Making the Site Feel Instant with Code‑Splitting
Use dynamic imports for heavy components like the contact form so the initial page loads fast; fetch complex code only when needed.
The Results: From "Poor" to Profitable
Our approach produced dramatic, measurable improvements in Core Web Vitals and conversions.
| Metric | Before | After | Improvement |
|---|---|---|---|
| Load Time (LCP) | 4.2s | 1.9s | 55% Faster |
| Stability (CLS) | 0.28 | 0.05 | 82% More Stable |
+15% leads in the 30 days following the rollout.
Your Next Step
High bounce rates or flat conversions? Your Core Web Vitals may be the culprit. A “good enough” website could be silently costing you customers.
Ready to replicate these gains? AI Vibe Code Repair & Optimization can apply the same techniques to your site — from image strategy and layout stability to code‑splitting — with measurable improvements. Prefer a ground‑up rebuild? Our Custom Web Design team delivers a fast, SEO‑first site.