What is INP by CPU performance
INP by CPU performance shows how Interaction to Next Paint (INP) varies depending on the estimated performance tier of the user's device CPU.
We group devices into:
High tier – High-end phones, modern desktops, and powerful laptops
Mid tier – Average mobile devices and older computers
Low tier – Budget phones and devices with limited processing capabilities
This lens reveals how responsive your site feels based on a user's hardware — especially when interacting with menus, forms, buttons, or other dynamic content.
Healthy INP by CPU performance sample
Should you worry
In a healthy case:
All CPU tiers have fast, responsive interactions
Mid and low tier devices might be slightly slower, but not frustratingly so
Your site handles event delegation and rendering efficiently across the board
This indicates good practices like:
Avoiding expensive input handlers
Keeping DOM complexity manageable
Minimizing long JavaScript tasks
Users shouldn’t have to own a flagship phone just to click a button without delay.
Unhealthy INP by CPU performance sample
If low or mid tier devices show red or yellow INP:
You likely have long-running JavaScript blocking interactivity
Input events (e.g. taps, clicks) might be triggering expensive re-renders
Reactivity and paint logic may not be optimized for underpowered devices
If high tier devices are also slow, it’s a red flag: your frontend may be over-engineered or suffering from code bloat that impacts everyone.
INP issues on weaker CPUs can easily go unnoticed unless this lens is checked — but they often hurt the largest segment of your user base
Resolving unhealthy INP by CPU performance
Go-to action plan to resolve an unhealthy INP by CPU performance:
Ask Uxi to analyze your INP by CPU performance values and suggest improvements.
Use Filters to isolate slow interactions on mid and low tier devices.
Simulate INP of the suspected lens to see if fixing it will resolve the INP by CPU performance. If yes, this is where the resolution focus should be.
Use an automated INP optimization tool like INProve to improve your INP by CPU performance values.
Once you’ve improved INP, 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.