LCP is configured to meet the 2.5s threshold
Why it matters
Largest Contentful Paint is Google's primary user-experience signal for search ranking and a direct measure of ISO-25010 time-behaviour. When LCP exceeds 2.5s, Google's data shows bounce rates climb sharply — 53% of mobile visitors abandon a page that takes more than 3s to load. For a marketing page, that abandoned visit represents lost acquisition revenue. An unoptimised hero image served over full SSR with no CDN is the most common culprit: it stacks TTFB latency on top of image download time, guaranteeing a failing score on both real-user monitoring and Lighthouse CI. Failing LCP also signals poor Core Web Vitals to the Google Search Console, which feeds directly into ranking demotion in the Page Experience system.
Severity rationale
Critical because a failing LCP score simultaneously harms Google search rankings and increases visitor bounce rates, making it the highest-leverage performance metric for marketing ROI.
Remediation
Add priority loading to the hero image and switch marketing pages to static generation so TTFB is served from CDN edge. In Next.js, the priority prop generates both fetchpriority="high" and a <link rel="preload"> automatically:
import Image from 'next/image'
// app/(marketing)/_components/hero.tsx
<Image
src="/hero.webp"
alt="Hero"
width={1200}
height={630}
priority
fetchPriority="high"
/>
Remove any export const dynamic = 'force-dynamic' from marketing page routes — static generation is the default and serves HTML from CDN edge in <50ms. Convert hero images to WebP with npx sharp-cli --input public/hero.jpg --output public/hero.webp --format webp if you haven't already.
DetectionPro
The detection method for this pattern is part of AuditBuffet Pro.
The full method (what to look for, pass and fail conditions, and how results get reported) ships inside the Page Speed Audit. The pattern definition, severity rationale, and remediation remain openly licensed under CC-BY-4.0.
External references
- iso-25010:2011 · performance-efficiency.time-behaviour — LCP ≤ 2.5s — time-behaviour sub-characteristic
Taxons
History
- 2026-04-18·v1.0.0·Initial import from marketing-page-speed·automated