www.cwi.nl/en speed test — 20 Oct 2026
Measured from the wfix.shop server on 20 October 2026 at 13:56 UTC. Grade D (60/100), with the screenshots, the timings and the fixes that matter.
Where the first byte went
- DNS lookup 82 ms 2%
- TCP connect 149 ms 4%
- Server wait 3.99 s 95%
Measured on the connection that fetched the HTML. Every other request on the page waits for the end of this bar before it can start.
How this page compares
Every report published here is in this comparison, so it is a reference population of pages tested from one server - not a benchmark of the whole web.
What these numbers mean
- The first byte took 4.22 s. Everything else waits for that number, so the server is where to start: caching, a slow query, or an overloaded host.
- The page transfers 993.2 KB over 22 request(s). Html files are 90% of it, so that one type is worth a look on its own.
- It runs over HTTP/2, so the assets share a connection instead of opening one each.
- The largest element took 5.80 s to paint, past the 2.5 s threshold: usually a hero image that is too big or a render-blocking script in front of it.
- Layout stayed still (CLS 0.094), so nothing jumps under the reader's cursor.
- The main thread was blocked for 2 ms in total, which is not enough to feel.
Fix first: Server response time (TTFB) - Cut server think time: page cache, query indexes, fewer synchronous calls to third parties inside the request. Connection setup is distance, so a nearer region or a CDN edge helps instead.
Read on one shared server, not a visitor's phone: use it to compare pages against each other, not as a promise about every connection. We fix what these tests find.
Screenshot
What the page looks like
Loaded in headless Chromium on this server. Click an image to open it full size.
Browser render
The same URL loaded in a real browser, so these are the readings curl cannot produce. The grade above is still built from the server measurements.
Page weight by type
What the page is made of
Transfer size, compressed as sent. 22 request(s) in total, 993.2 KB across all of them.
Top issues
Server response time (TTFB)
high impactThe first byte arrived after 4219 ms. Of that, 3988 ms was the server thinking and 231 ms was connection setup. A first byte under 400 ms is what a visitor feels as instant.
Fix: Cut server think time: page cache, query indexes, fewer synchronous calls to third parties inside the request. Connection setup is distance, so a nearer region or a CDN edge helps instead.
Compress text responses
high impact0 text response(s) of 10 KB or more are sent uncompressed, and the document itself is compressed. That is 0 B of compressible text.
Fix: Turn on brotli (preferred) or gzip for text/css, javascript and text/html in the web server. This is the cheapest win available on almost any site.
Total page weight
medium impactThe page transfers 993.2 KB across 22 request(s), with the document itself at 79.4 KB.
Fix: Work through the heaviest assets first: images, then fonts, then third-party scripts.
Cache static assets
medium impact1 asset(s) answer without a Cache-Control max-age, so browsers revalidate them on every visit.
Fix: Version filenames on change and serve them with a long max-age plus immutable. That is what makes a returning visitor fast.
Avoid extra redirects
medium impact2 redirect hop(s) before the page load started, each one a full round trip before the first byte.
Fix: Link to the canonical URL (and make sure http, the apex domain and www all point at it) so no visitor pays a redirect first.
Waterfall
Slowest requests
Each bar is one request's own response time, scaled to the slowest. Assets were fetched in parallel, so the bars overlap in real time rather than stacking. first party third party
| Request | Type | Status | Time | Size |
|---|---|---|---|---|
| https://stats.cwi.nl/piwik.php?idsite=1 3rd party | images | 200 | 1.25 s | 43 B |
| https://www.cwi.nl/en/static/images/logos/cwi-logo-english-white.svg | html | 404 | 1.24 s | 47.2 KB |
| https://www.cwi.nl/en/static/images/nwo-logo.svg | html | 404 | 1.23 s | 47.2 KB |
| https://www.cwi.nl/en/images/34465/221208-headerbeeld-07.2e16d0ba.fill-1920x866.jpg | html | 404 | 1.15 s | 47.2 KB |
| https://www.cwi.nl/en/images/60832/Bert_Zwart_Stochastics.2e16d0ba.fill-427x427.jpg | html | 404 | 1.15 s | 47.2 KB |
| https://www.cwi.nl/en/images/60743/1790236284986.2e16d0ba.fill-427x427.jpg | html | 404 | 1.14 s | 47.2 KB |
| https://www.cwi.nl/en/images/34776/header_gebouw.2e16d0ba.fill-427x427.jpg | html | 404 | 1.14 s | 47.2 KB |
| https://www.cwi.nl/en/documents/200032/80_YearLogo_Teal_Text_alleen_voor_website.svg | html | 404 | 1.13 s | 47.2 KB |
| https://www.cwi.nl/en/static/images/triangle.svg | html | 404 | 1.13 s | 47.2 KB |
| https://www.cwi.nl/en/images/58188/Algemeen_CWI_2025_06_04-008.2e16d0ba.fill-1920x866.jpg | html | 404 | 1.11 s | 47.2 KB |
| https://www.cwi.nl/en/images/59192/We_At_CWI_April_2026_Sanne_Vrijen.2e16d0ba.fill-1920x866.jpg | html | 404 | 1.11 s | 47.2 KB |
| https://www.cwi.nl/en/static/images/favicon-180.png | html | 404 | 1.07 s | 47.2 KB |
| https://www.cwi.nl/en/static/images/favicon.ico | html | 404 | 1.07 s | 47.2 KB |
| https://www.cwi.nl/en/images/58189/DIS-groep_CWI_2025_06_04-014.2e16d0ba.fill-1920x866.jpg | html | 404 | 1.07 s | 47.2 KB |
| https://www.cwi.nl/en/jsi18n/ | html | 404 | 1.07 s | 47.2 KB |
| https://www.cwi.nl/en/images/58186/Algemeen_CWI_2025_06_04-017.2e16d0ba.fill-1920x866.jpg | html | 404 | 1.07 s | 47.2 KB |
| https://www.cwi.nl/en/static/main-c4db4aa6310f0cf78ada.js | html | 404 | 1.07 s | 47.2 KB |
| https://www.cwi.nl/en/static/images/favicon.svg | html | 404 | 1.07 s | 47.2 KB |
| https://www.cwi.nl/en/static/main-c4db4aa6310f0cf78ada.css | html | 404 | 1.05 s | 47.2 KB |
| https://www.cwi.nl/en/images/44766/221208-headerbeeld-15.d59e16b8.fill-427x427.jpg | html | 404 | 927 ms | 47.2 KB |
| https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.9/MathJax.js?config=TeX-MML-AM_CHTML 3rd party | javascript | 200 | 896 ms | 16.6 KB |
Report this page
Run this test on your own site
The same engine, free, with the screenshots and the fixes. No account needed.