The Performance dimension accounts for 20% of the WIS™ composite score. It measures eight server-side signals detectable from HTTP headers and response metadata — no browser rendering required. Each signal is weighted by its real-world impact on load time, Core Web Vitals, and SEO rankings.
Performance Score Formula
performance_score = Σ(signal_points × confidence) / max_points × 100Max points: 100 · TTFB contributes ±20 pts dynamically · All other signals are binary (present/absent)
Click any signal to expand its description, fix recommendation, and example header value.
SiteReveal focuses on server-side signals measurable in under 10 seconds. For full Core Web Vitals and waterfall analysis, combine with GTmetrix or PageSpeed Insights.
| Signal | SiteReveal | GTmetrix | PageSpeed | WebPageTest |
|---|---|---|---|---|
| TTFB measurement | ||||
| CDN detection | ||||
| Compression check | ||||
| HTTP/2 detection | ||||
| Cache-Control analysis | ||||
| Image format check | ||||
| Redirect chain count | ||||
| Core Web Vitals (LCP/CLS/FID) | ||||
| Waterfall chart | ||||
| Composite WIS™ score |
SiteReveal measures performance using eight server-side signals detectable from HTTP headers and response metadata: TTFB, CDN presence, compression (Gzip/Brotli), HTTP/2 support, Cache-Control headers, image optimisation signals, redirect chain length, and server type. Each signal is weighted by its real-world impact on load time and combined into a 0–100 Performance sub-score.
Core Web Vitals require a full browser rendering session with JavaScript execution and layout calculation — they cannot be measured from HTTP headers alone. SiteReveal's server-side scan is designed to be fast (under 10 seconds) and work on any URL without requiring a headless browser for every scan. For full Core Web Vitals measurement, use Google PageSpeed Insights or GTmetrix alongside SiteReveal.
Scores above 80 indicate a well-optimised site with CDN, compression, HTTP/2, and good caching in place. Scores between 60–79 suggest one or two missing optimisations (typically CDN or compression). Scores below 60 indicate multiple gaps — usually no CDN, no compression, or very slow TTFB — that will materially impact user experience and SEO rankings.
TTFB is scored on a tiered scale: excellent (<800ms) adds +10 points, good (800ms–2s) is neutral, poor (2s–3s) subtracts 5 points, very poor (3s–5s) subtracts 10 points, and critical (>5s) subtracts 20 points. This reflects Google's own TTFB guidance where >800ms is considered 'needs improvement' and >1.8s is 'poor'.
Run a free scan and see exactly which performance signals your site is missing — with prioritised fix recommendations.
Also see: Security Scoring Methodology · SEO Scoring Methodology · Full WIS™ Methodology
