Why is my page slower after installing SmartVideo?

SmartVideo is built not to slow your page down. The player loads asynchronously, so the rest of your page keeps rendering while it downloads, and it ships no third-party ad code by default. In our Lighthouse benchmark of a realistic blog page with one video, the SmartVideo page weighed about half as much as the same page with a YouTube embed and at least 15% less than with a Vimeo embed, with fewer requests than either.

To keep your layout steady, give the video’s space a size in your CSS so the player has room before it appears. Our WordPress plugin (version 2.3 and later) does this for responsive videos. On other sites, one rule does it: smartvideo { display: block; aspect-ratio: 16 / 9; }, using your video’s shape.

If your score dropped after installing SmartVideo, the steps below show you how to find which metric moved and why, and what to send us so we can help.

Know what you’re measuring

GTmetrix reports a Fully Loaded Time, which keeps running until the page stops transferring data entirely. Anything still downloading after the page is visible and usable, such as video data, keeps that clock going. GTmetrix’s own documentation notes that a page can load fast and be usable while the reported load time comes out longer. Compare the metrics PageSpeed Insights reports instead: LCP, CLS, and Total Blocking Time.

PageSpeed Insights shows two kinds of results:

• Lab results: The Performance score comes from Lighthouse testing your page under simulated device and network conditions. Scores vary between runs, so use the individual metrics and diagnostics, not one score, to investigate a change.
• Field results: Core Web Vitals measure real visitors’ loading (LCP), responsiveness (INP), and visual stability (CLS) over the previous 28 days, from the Chrome User Experience Report (CrUX). Search Console’s Core Web Vitals report uses the same data, grouped across similar pages.

Field data won’t reflect a change you made today. If your page has too few visits, PageSpeed shows data for the whole site (the origin) or no field data at all, so check which one you’re looking at before comparing.

Google uses Core Web Vitals in its ranking systems, not the Lighthouse Performance score. Treat the lab score as a diagnostic tool, not a ranking score. See Google’s page experience FAQ and how PageSpeed measures performance.

Check your page

1. Compare with and without SmartVideo. On a test copy of the page, run PageSpeed with SmartVideo enabled and disabled, keeping everything else the same. Compare mobile with mobile or desktop with desktop, run each version more than once, and save the report links. If SmartVideo replaced a YouTube or Vimeo embed, test the page with that original embed; otherwise note that your comparison page has no video. PageSpeed loads the page from Google’s servers, so don’t password-protect the test copy.
2. Find the metric that moved. Compare LCP, CLS, and Total Blocking Time, not just the overall score, and use the report’s diagnostics to find the element or script responsible. Field INP measures real visitors’ responsiveness and is a different metric from lab Total Blocking Time.
3. Check the poster image and layout. If the report names the video poster as the LCP element, check that the intended image appears from a publicly accessible URL and that the file is compressed and sized to the player’s display width. Set it with the poster option or the WordPress block’s Poster setting. If CLS increased, the report’s layout shift diagnostic names the elements that moved. If the video area is one of them, reserve its space with the CSS rule above; a <smartvideo> tag has no size of its own until the player script runs.
4. Test autoplay and player count. Autoplay starts playback without a click, so the video loads with the page. Turn it off and retest: for a manual tag, remove autoplay and keep controls; in the WordPress block, turn off the Autoplay toggle (playback options). If the page has several players, compare a test copy with one player against the normal version.
5. Note optimization plugins. List any caching, minification, or lazy-loading plugin that touches the page, such as Autoptimize, WP Rocket, or LiteSpeed Cache. Settings that delay or combine scripts change when the player loads and what PageSpeed measures. If videos also fail to play or load inconsistently, follow the plugin fixes in the troubleshooting guide.

Send us a useful report

Email support@swarmify.com or use the message widget on this page. Include:

• The affected page URL.
• The PageSpeed report link, plus the comparison report with SmartVideo disabled if you have one.
• Whether you tested mobile or desktop, which metrics changed, and when you installed SmartVideo.
• The number of players, whether autoplay is enabled, and any lazy-loading or optimization plugins involved.

For other details that help us find your setup, see how to get support.

Keywords: GT Metrix, latency, page speed, pagespeed, speedtest, speed test, CLS, layout shift, Core Web Vitals