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WebpageTest vs. Google PageSpeed Insights - Printable Version

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WebpageTest vs. Google PageSpeed Insights - nicolesharp100 - 03-26-2018 08:00 AM

How accurate is WebpageTest for identifying performance issues? WebpageTest is claiming a 6-second page-load time for MediaWiki, but Google PageSpeed Insights says that is "good" with a 90% performance rating. https://developers.google.com/speed/pagespeed/insights/


RE: WebpageTest vs. Google PageSpeed Insights - nicolesharp100 - 03-28-2018 11:01 AM

Here is a pretty huge difference: https://sandbox.nicolesharp.net/wiki/project:sandbox/gallery

WebpageTest says it takes up to 105 seconds (!!!) for the first-view loadtime. But Google PageSpeed Insights says that is "medium" performance with a score of 78%, and actually "good" mobile performance, with a mobile score of 84%.

Looking at the WebpageTest results, it would seem like there are serious performance problems that would make it difficult for people to access the website. But Google PageSpeed Insights says that the website has "medium" to "good" performance, with average performance scores above 75%.

Here is the exact same page hosted by Wikimedia: https://www.mediawiki.org/wiki/user:Nicole_Sharp/sandbox/gallery

WebpageTest says that the page on MediaWiki.org takes a mere 1 second to load, but Google PageSpeed Insights gives a nearly identical score (only a 1% difference) between the page hosted on MediaWiki.org versus NicoleSharp.net.

So if I only go by the Google PageSpeed Insights score, it would seem that my website performs similarly to Wikimedia's MediaWiki.org. But WebpageTest provides a dramatically different conclusion that is much more worrisome. What might be causing the difference? Should I trust Google over WebpageTest?


Web page performance - vinay.krishnamurthy - 03-29-2018 04:18 PM

How do we test the performance of web page when the URL is same for every other page in an application


RE: WebpageTest vs. Google PageSpeed Insights - MachMetrics - 04-05-2018 05:01 AM

Any two speed testing services are going to give you different results. They have different methods of testing, are ran on different networks, etc. WPT allows you to simulate multiple devices and throttle network bandwidth, while GPSI just gives you a desktop and mobile result.

That being said, I have noticed some inconsistent results within the public WPT.org. If you love WPT but want it more consistent, try setting up a private instance, or use a premium monitoring service like SpeedCurve or MachMetrics.

Important thing is to pick one tool and check it over time, that's the only way to ensure you're tackling your page speed from both an offensive and defensive approach.