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Largest Contentful Paint numbers don't reflect what is seen in the video - Printable Version

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Largest Contentful Paint numbers don't reflect what is seen in the video - satishsgws - 07-08-2020 04:09 AM

Hi Pat,
can you check https://www.webpagetest.org/result/200707_8Y_3a178bb49ea2e11c63e7bcaeb87c47dd/

It reports LCP as 1.84s.. but the video shows content rendering only at 5th second.

https://www.webpagetest.org/video/view.php?id=200707_8Y_3a178bb49ea2e11c63e7bcaeb87c47dd.1.0


RE: Largest Contentful Paint numbers don't reflect what is seen in the video - pmeenan - 07-09-2020 01:58 AM

Hard to know for sure without looking at how the page works but my guess is this Chrome bug: https://bugs.chromium.org/p/chromium/issues/detail?id=1092473&q=&can=4

If the page is hidden by setting opacity to 0 and then revealed later, Crome will (incorrectly) count the hidden paints.


RE: Largest Contentful Paint numbers don't reflect what is seen in the video - satishsgws - 07-09-2020 11:07 AM

whoa.. that's a huge bug. Thanks for filing it and getting the Chromium devs to think of a fix.

Maybe this site is using Google Optimize .. maybe it is deliberately setting Opacity to 0.. will check.

will i be able to find that by using the Performance profiler in Chrome? It will be very useful to report on how long that piece of A/B code was executing.

whoa.. that's a huge bug. Thanks for filing it and getting the Chromium devs to think of a fix.

Maybe this site is using Google Optimize .. maybe it is deliberately setting Opacity to 0.. will check.

will i be able to find that by using the Performance profiler in Chrome? It will be very useful to report on how long that piece of A/B code was executing.