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PLS with cookies on/off

PLS with cookies on/off without noise

Vasil Dachev avatar
Written by Vasil Dachev
Updated over a week ago


What is PLS with cookies on/off

PLS with cookies on/off compares Perceived Load Speed (PLS) based on whether the user’s browser has cookies enabled or disabled.

While cookies typically help personalize the user experience, they can also introduce additional scripts, third-party trackers, or conditional rendering logic. This lens helps you understand whether those differences in behavior affect how fast the page feels to real users.

PLS (Perceived Load Speed) measures how quickly a page feels visually complete — so if cookie-based personalization slows things down, this lens will expose it.



Healthy PLS with cookies on/off sample


Should you worry

If PLS values are similar whether cookies are enabled or disabled, your site is handling both scenarios efficiently — without sacrificing speed for personalization or tracking.

However, if enabling cookies leads to significantly slower perceived load times, it could indicate that personalized elements, marketing scripts, or cookie banners are hurting the experience.

Unhealthy PLS with cookies on/off sample

When users with cookies enabled experience noticeably slower PLS, it often points to:

  • Additional third-party trackers being injected

  • Deferred or conditional rendering based on cookies

  • Performance-heavy personalization logic

  • Cookie consent banners blocking the view or delaying layout shifts

These can delay when the page looks and feels complete — especially for first-time visitors.

Resolving unhealthy PLS with cookies on/off

Go-to action plan to resolve an unhealthy PLS with cookies on/off:

  1. Ask Uxi to analyze your PLS with cookies on/off and suggest improvements.

  2. Use Filters to isolate cookie-enabled users and identify pages with high traffic and slow PLS.

  3. Simulate LCP of the suspected lens to see if fixing it will resolve the PLS with cookies on/off. If yes, this is where the resolution focus should be.

  4. Use an automated optimization tool like Navigation AI to improve your PLS with cookies on/off.

  5. Once you’ve improved PLS, set an alert to be the first to know if it starts worsening again.

Try it yourself

Discover how your website performs with real user data.

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