Watch for changes
rockefeller.edu loads faster with WebSpeed
Measured PageSpeed before and after WebSpeed optimization — no plugins, no migration.
Speed Index from a single check. Repeat checks of the same page typically differ by around 30%, so read the two times as a direction, not a precise multiplier.
From the measured LCP gain: −27.8 s.
Core Web Vitals are a Google ranking signal, but work as a “tiebreaker” — they matter most when two pages are roughly equal in relevance and content. The biggest SEO benefit comes from moving out of the Poor zone (score < 50).
From the measured LCP gain: −27.8 s.
Google / Deloitte (2019): 0.1 s improvement → +8% conversions in retail. Portent: each extra second of load time reduces conversion rate ~4%.
From the measured LCP gain: −27.8 s.
Based on Google data: pages loading in 3 s vs 1 s show ~32% higher bounce rate. Estimate scales proportionally to LCP improvement and is site-specific.
From the measured page weight: ≈ 11 → 4.2 g per visit.
Transferred bytes × ≈0.5 g of CO₂ per MB, a common average for networks and devices. The real figure depends on the hosting and the visitor’s connection.
Forecasts, not measurements: measured gains × published studies — tap any underlined label for the source.
Lighthouse recording of the original page under real mobile throttling. The right panel replays the same frames at the measured Speed Index ratio (3.3× faster). Played back 4.6× faster than real time — both panels equally.
Fastest quarter 80+ · you 55
Fastest quarter 96+ · you 51
Fastest quarter ≤ 3.4 s · you 16.5 s
Fastest quarter ≤ 0.9 s · you 1.3 s
Fastest quarter ≤ 3.7 s · you 61.7 s
Fastest quarter ≤ 0.9 s · you 7.2 s
Fastest quarter ≤ 1.1 MB · you 22.4 MB
Fastest quarter ≤ 1.3 MB · you 25.7 MB
Based on 2844 WordPress sites WebSpeed has measured, as they are, without our optimization. Updated 9 Nov 2026.
Speed
what the visitor sees| Metric | Now | Fast | Δ |
|---|---|---|---|
| PageSpeed scoreblends the five below | 55 | 67 | +12 |
| First Contentful Paint. The moment the browser renders the first piece of real content — the first sign to the visitor that the page is loading.≤ 1.8s | 16.5 s | 3.6 s | −78% |
| Largest Contentful Paint. The time it takes for the largest image or text block in the viewport to render — one of Google's three Core Web Vitals.≤ 2.5s | 61.7 s | 6.6 s | −89% |
| How quickly the visible part of the page fills in during load, averaged over time — a lab metric that rewards showing content sooner.≤ 3.4s | 16.5 s | 4.9 s | −70% |
| Total Blocking Time. The total time the main thread was blocked by long tasks during load — the lab metric that stands in for real-world responsiveness.≤ 200ms | 40 ms | 60 ms | No change beyond run-to-run noise. |
| Cumulative Layout Shift. A score for how much visible content unexpectedly jumps around while the page loads — one of Google's three Core Web Vitals.≤ 0.1 | 0 | 0 | No change beyond run-to-run noise. |
| LCP breakdownobserved load, no throttling | |||
| What the largest visible element was — an image or a block of text. The two are sped up by different means. | Image | Image | same |
| Time until the first byte of the HTML arrived.TTFB | 3 ms | 14 ms | No change beyond run-to-run noise. |
| Time between the first byte and the moment the browser started downloading the LCP image. Long when the image is found late — lazy-loaded, set from CSS or JS.until the image is requested | 999 ms | 1.6 s | +56% |
| Time spent downloading the LCP image itself — its weight and the connection.downloading the image | 402 ms | 572 ms | +42% |
| Time between the resource being ready and the element being painted — blocked by CSS, fonts or scripts.until it is painted | 957 ms | 207 ms | −78% |
Page weight
loaded during the test| Metric | Now | Fast | Δ |
|---|---|---|---|
| Files the browser downloaded during the test. | 74 | 38 | −36 |
| The page itself, before anything it references. | 280 KB | 122 KB | −72% |
| Scripts downloaded during the test. Fewer can mean deferred past the test window, not removed from the site. | 141.2 MB | 6231 KB | −82% |
| Stylesheets downloaded during the test. | 5176 KB | 2110 KB | −37% |
| Web font files downloaded during the test. | 201.9 MB | 5216 KB | −89% |
| Images downloaded during the test. Images below the fold may load later, after the test. | 2219.2 MB | 217.8 MB | −59% |
| Third-partyother companies’ servers | |||
| Distinct third-party domains the page downloaded from — analytics, chat, embeds, fonts, CDNs. | 13 | 6 | −7 |
| Bytes downloaded from those third-party domains. | 2.9 MB | 129 KB | −96% |
What holds the main thread
Lighthouse attribution, lab run| Time a script kept the browser busy beyond 50 ms per task — the same pieces Lighthouse adds up into Total Blocking Time. While it lasts, taps and clicks wait. Counted on the recorded run, so the total can differ from the simulated TBT above. | Now | Fast |
|---|---|---|
| YouTubeThird-party service · Video | 181 ms | 0 ms |
| The site’s own scripts, plugins and services not listed above (each under 50 ms or past the top three), and browser work Lighthouse could not tie to any script.Site’s own code, smaller scripts, unattributed | 85 ms | 93 ms |
Fast removes nothing: every script still loads and runs, and Fast starts what it safely can after the page is ready to use.
Each number comes from one lab run. A script that ran after the run ended shows 0 ms.
Already on this site
Original page, before Fast- WP Super CacheCaching and optimisation plugin
- Main image is marked high priorityMissingWP Super Cache doesn't mark the main image as high priority; it only caches pages. Source
- Images are in modern formats and sized to the screenMissingLighthouse estimate: −14.5 s LCPWP Super Cache doesn't convert or resize images; that takes a separate image plugin or image CDN. Source
- No CSS or JS holds back the first paintMissingWP Super Cache doesn't defer scripts or inline critical CSS; that takes a separate optimization plugin. Source
- Static files are cached in the browserMissingLighthouse estimate: −39.4 s LCPWP Super Cache doesn't set browser-cache headers for static files; it only sets short headers on cached pages. Source
- CSS and JS are minifiedMissingLighthouse estimate: −15 KBWP Super Cache doesn't minify CSS or JavaScript; that takes a separate optimization plugin. Source
- Text stays visible while web fonts loadMissingWP Super Cache doesn't change how web fonts load; it only caches pages. Source
- Main image is in the HTML, not added by a scriptOK
- Main image is not lazy-loadedOK
- The page is compressed (gzip or brotli)OK
- Admin area
/wp-admin/and/wp-login.phppass through Fast unchanged and are never cached
Tools are recognised from the page’s code and response headers. A tool that leaves no trace there is not listed.
“OK” means Lighthouse found nothing to fix on the original page — not that someone switched it on.
Savings are Lighthouse’s own estimates for the original page, not measured by us.
Speed
what the visitor sees| Metric | Now | Fast | Δ |
|---|---|---|---|
| PageSpeed scoreblends the five below | 51 | 75 | +24 |
| First Contentful Paint. The moment the browser renders the first piece of real content — the first sign to the visitor that the page is loading.≤ 1.8s | 0.8 s | 0.6 s | −20% |
| Largest Contentful Paint. The time it takes for the largest image or text block in the viewport to render — one of Google's three Core Web Vitals.≤ 2.5s | 7.2 s | 6.7 s | No change beyond run-to-run noise. |
| How quickly the visible part of the page fills in during load, averaged over time — a lab metric that rewards showing content sooner.≤ 3.4s | 1.3 s | 1.2 s | No change beyond run-to-run noise. |
| Total Blocking Time. The total time the main thread was blocked by long tasks during load — the lab metric that stands in for real-world responsiveness.≤ 200ms | 570 ms | 30 ms | −94% |
| Cumulative Layout Shift. A score for how much visible content unexpectedly jumps around while the page loads — one of Google's three Core Web Vitals.≤ 0.1 | 0.025 | 0.026 | No change beyond run-to-run noise. |
| LCP breakdownobserved load, no throttling | |||
| What the largest visible element was — an image or a block of text. The two are sped up by different means. | Image | Image | same |
| Time until the first byte of the HTML arrived.TTFB | 3 ms | 4 ms | No change beyond run-to-run noise. |
| Time between the first byte and the moment the browser started downloading the LCP image. Long when the image is found late — lazy-loaded, set from CSS or JS.until the image is requested | 1.1 s | 1.1 s | No change beyond run-to-run noise. |
| Time spent downloading the LCP image itself — its weight and the connection.downloading the image | 117 ms | 15 ms | −87% |
| Time between the resource being ready and the element being painted — blocked by CSS, fonts or scripts.until it is painted | 116 ms | 127 ms | No change beyond run-to-run noise. |
Page weight
loaded during the test| Metric | Now | Fast | Δ |
|---|---|---|---|
| Files the browser downloaded during the test. | 87 | 49 | −38 |
| The page itself, before anything it references. | 279 KB | 122 KB | −72% |
| Scripts downloaded during the test. Fewer can mean deferred past the test window, not removed from the site. | 141.2 MB | 6231 KB | −82% |
| Stylesheets downloaded during the test. | 5179 KB | 2110 KB | −38% |
| Web font files downloaded during the test. | 211.5 MB | 4204 KB | −87% |
| Images downloaded during the test. Images below the fold may load later, after the test. | 3422.7 MB | 339.3 MB | −59% |
| Third-partyother companies’ servers | |||
| Distinct third-party domains the page downloaded from — analytics, chat, embeds, fonts, CDNs. | 13 | 6 | −7 |
| Bytes downloaded from those third-party domains. | 2.6 MB | 117 KB | −96% |
What holds the main thread
Lighthouse attribution, lab run| Time a script kept the browser busy beyond 50 ms per task — the same pieces Lighthouse adds up into Total Blocking Time. While it lasts, taps and clicks wait. Counted on the recorded run, so the total can differ from the simulated TBT above. | Now | Fast |
|---|---|---|
| YouTubeThird-party service · Video | 384 ms | 0 ms |
| Google Tag Manager, plus the tags it loads: analytics, ads, chat. Time counts here when it runs inside GTM’s own script. Fast does not remove it: every tag still fires.Third-party service · Tag manager | 108 ms | 0 ms |
| The site’s own scripts, plugins and services not listed above (each under 50 ms or past the top three), and browser work Lighthouse could not tie to any script.Site’s own code, smaller scripts, unattributed | 91 ms | 34 ms |
Fast removes nothing: every script still loads and runs, and Fast starts what it safely can after the page is ready to use.
Each number comes from one lab run. A script that ran after the run ended shows 0 ms.
Already on this site
Original page, before Fast- WP Super CacheCaching and optimisation plugin
- Main image is marked high priorityMissingWP Super Cache doesn't mark the main image as high priority; it only caches pages. Source
- Images are in modern formats and sized to the screenMissingLighthouse estimate: −750 ms LCPWP Super Cache doesn't convert or resize images; that takes a separate image plugin or image CDN. Source
- No CSS or JS holds back the first paintMissingWP Super Cache doesn't defer scripts or inline critical CSS; that takes a separate optimization plugin. Source
- Static files are cached in the browserMissingLighthouse estimate: −4.7 s LCPWP Super Cache doesn't set browser-cache headers for static files; it only sets short headers on cached pages. Source
- CSS and JS are minifiedMissingLighthouse estimate: −15 KBWP Super Cache doesn't minify CSS or JavaScript; that takes a separate optimization plugin. Source
- Text stays visible while web fonts loadMissingWP Super Cache doesn't change how web fonts load; it only caches pages. Source
- Main image is in the HTML, not added by a scriptOK
- Main image is not lazy-loadedOK
- The page is compressed (gzip or brotli)OK
- Admin area
/wp-admin/and/wp-login.phppass through Fast unchanged and are never cached
Tools are recognised from the page’s code and response headers. A tool that leaves no trace there is not listed.
“OK” means Lighthouse found nothing to fix on the original page — not that someone switched it on.
Savings are Lighthouse’s own estimates for the original page, not measured by us.
PageSpeed scores are measured by Google PageSpeed Insights and are not guaranteed: they vary run to run and depend on network, device and third-party code. How to read this report
PageSpeed 55 → 67 on mobile, the screen fills in 4.9 s instead of 16.5 s on mobile, the page weighs 8.4 MB instead of 22.4 MB and the main content appears in 6.6 s instead of 61.7 s on mobile.
Still on the site itself: the main image is not marked high priority, images are not in modern formats or sized to the screen, CSS or JS holds back the first paint, and 3 more — listed under “Already on this site” in Speed metrics.
Get this speed for your visitors — WebSpeed Fast, 14 days free. Edit the page code yourself — the report lists the changes.
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The before/after check is free to run; it isn’t one of these plans. Choose a plan when you’re ready to make the speed-up permanent — or buy the report once and apply it yourself.
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