Chrome extensions can significantly slow down browsing – gHacks Tech News

Extensions are one of the greatest strengths of web browsers. They allow users to expand functionality, but this comes at a cost. A test of the 5,000 most popular Chrome extensions found that extensions can significantly slow down the browsing experience, with one notable exception.

The team at Debugbear analyzed the performance impact of Chrome extensions in several ways, including the impact on CPU processing and website loading time.

Here are the most important findings:

• Even on simple websites, some Chrome extensions added 500ms or more to processing time.
• 86% of extensions tested have minimal impact on simple websites.
• 1.7% of extensions add 500 ms or more to the processing of simple websites.
• On complex websites, processing time reached 2000 ms.
• The impact may be cumulative, meaning multiple expansions may have a greater impact on the experience.
• Popular extensions with high processing times: Honey Automatic Coupons, Klarna Pay Later, Monica – Your AI Copilot, Capital One Shopping, Popup Blocker, Dark Theme, Malwarebytes, Dark Reader, DDG Privacy Essentials.
• One type of extension reduces website processing: content blockers.
• Extensions can affect any browser, including other Chromium-based browsers and Firefox-based browsers.

Impact on website loading time

Browser extensions can slow down website loading time, especially if they are designed to run when the page loads rather than when the page content is displayed to the user.

• Extensions can add up to 1000ms to the loading time of simple websites.
• Chrome extensions can also delay interactions after a website has loaded. However, this is less common and the impact is less than 50ms for all but a few extensions.

This delay is noticeable to the user as it takes longer for website content to be displayed by the browser.

Most content blockers improve the user experience

Content blockers significantly improve the CPU processing of websites and the page download page, especially on ad-heavy websites.

• Some content blockers reduced processing time from over 50 seconds to just a few seconds.
• Most have reduced page size from over 40MB to less than 5MB.
• Most reduce memory consumption.
• Notable extensions with good performance were: uBlock Origin, ScriptSafe, Privacy Badger, Malwarebytes.
• The popular AdBlock Plus and AdBlock extensions performed worse and were not much better than those of the browser without extensions.

The reason for the poor performance of AdBlock Plus is the Acceptable Advertising program, which allows some advertisements to be displayed while the content blocker is active. This can be disabled, which should improve performance.

The reason ScriptSafe performs best is because it blocks JavaScript by default.

Further insights

The researchers also analyzed memory usage and the impact on browser functionality.

• 86.6 percent of Chrome extensions use less than 10 MB of memory.
• 2.2 percent of Chrome extensions use more than 50 MB of memory.
• 6 extensions with more than 1 million break-back/forward cache: LastPass Password Manager, Avast Online Security, Avira Browser Safety, Norton Password Manager, Snap & Read, Microsoft Editor.

Final words

Installing browser extensions can affect how websites process and load. This has been known for a long time, but it is still important.

Content blockers improve both metrics because they primarily prevent JavaScript-heavy content from loading.

Some extensions can delay website loading by 1 second or more. Although this is the exception, users who run these may want to look for alternatives that have less impact.

Another useful option is to limit the execution of extensions to specific sites or only “on click”.

What about you? Are you running browser extensions? Do they affect website loading?

Advertising