Performance
Lab data — simulated mobile 42
Before 63 After
Lab metrics
Metric
Before
With Turbulence
Speed Index SI
Before: 5.8 s
After: 5.7 s -1%
First Contentful Paint FCP
Before: 3.6 s
After: 3.0 s -16%
Largest Contentful Paint LCP
Before: 16 s
After: 14 s -8%
Cumulative Layout Shift CLS
Before: 0.486
After: 0.000 -100%
Total Blocking Time TBT
Before: 66 ms
After: 169 ms
What changed (7)
- Speculation rules prefetching Browser prefetches likely navigation targets for instant loads
- Resource hints injected Browser knows what to fetch early
- Images re-encoded to AVIF/WebP Smaller image files that look the same
- Images re-encoded to AVIF/WebP Smaller image files that look the same
- Off-screen images lazy-loaded Images load as they scroll into view
- Image dimensions explicitly set Explicit dimensions prevent layout shifts
- Font display swap + DNS preconnect Text shows up while fonts load
How we measured this
- 1. We fetched your page and scored it with PageSpeed Insights (mobile, lab data).
- 2. We re-fetched it through a Turbulence preview environment that applies our transformation pipeline.
- 3. We scored the result with PageSpeed Insights again.
- 4. The deltas above are the difference — a directional estimate, not a forecast. First visits, geographic location, network conditions, and JS-rendered content all affect real-world results.