What is LCP by CPU performance
LCP by CPU performance shows how the Largest Contentful Paint (LCP) varies depending on the estimated performance tier of the user's device CPU.
We classify devices into three tiers:
High tier – Modern desktops, flagship phones, and high-end laptops.
Mid tier – Average smartphones and older laptops.
Low tier – Budget smartphones or entry-level devices, typically with limited processing power.
This lens helps you understand how well your site handles resource constraints — and whether you're unintentionally penalizing users on lower-end devices.
Healthy LCP by CPU performance sample
Should you worry
In a healthy LCP by CPU performance view, all three tiers show mostly green, even if mid and low tier devices are slightly slower. That’s a good sign your site is:
Efficiently structured and not over-reliant on client-side JS.
Rendering fast on weaker hardware by avoiding expensive runtime operations.
Designed with progressive enhancement in mind, gracefully adapting to performance ceilings.
High-tier users should feel instant, but low-tier users should never feel abandoned - that’s the bar.
Unhealthy LCP by CPU performance sample
If low or mid tier users show significant red or yellow, it often means:
You’re relying heavily on JavaScript-based layout rendering, which punishes slower CPUs.
Heavy components like carousels, animations, or third-party scripts are not being deferred or optimized for performance-constrained environments.
There may be no server-side fallback, causing devices to do all the heavy lifting client-side.
And when even high tier devices struggle, it’s a sign of global layout or code inefficiencies that impact everyone - regardless of power.
Resolving unhealthy LCP by CPU performance
Go-to action plan to resolve an unhealthy LCP by CPU performance:
Ask Uxi to analyze your LCP by CPU performance values and suggest improvements.
Use Filters to focus on low or mid tier device users, then trace the slowest LCP back to specific LCP lenses.
Simulate LCP of the suspected lens to see if fixing it will resolve the slow LCP by CPU performance. If yes, this is where the resolution focus should be.
Use an automated LCP optimization tool like Navigation AI to improve your LCP by CPU performance values.
Once you’ve improved LCP, 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.