YouTube Responds Too Slowly on Firefox Sometimes

Question

Sometimes YouTube takes too long to display results for a search query or change to a video page.

I noticed the following warnings in the developer console. The first one shows up after a few seconds I believe:

Source map error: Error: request failed with status 404
Resource URL: https://www.youtube.com/results?search_query=something
Source Map URL: yt-live-chat-default-theme.css.map

And this other warning that shows up when the page finally loads:

Will-change memory consumption is too high. Budget limit is the document surface area multiplied by 3 (738304 px). Occurrences of will-change over the budget will be ignored.

I am running Firefox with some privacy settings in about:config and uBlock Origin on Windows 10.

Answer 1

The first error is related only to DevTools, so does not relate to YouTube. You can avoid it, but it doesn't really matter. You may read more about it in the StackOverflow post Error message "DevTools failed to load SourceMap: Could not load content for chrome-extension://...".

The second error is more serious and relates to the CSS tag will-change.

This CSS tag tells your browser in advance that "this part of the page is going to animate, you can render it in advance". It should be used sparingly for animations and may cause performance issues because of excessive memory usage.

You cannot fix this error, since it comes from the YouTube website itself. If you know CSS and Javascript and can locate the place where YouTube uses will-change, you may use Greasemonkey to remove it.

Otherwise, you should investigate why there is not enough memory for running YouTube. Perhaps memory is being gobbled up by some other running application.

You could also try this in another browser, Microsoft Edge or Chrome, to see if they can run with less memory (or if they implement this CSS tag more efficiently than Firefox).