What is the First CPU Idle?

When loading a webpage, the first CPU idle is a measurement of the time it takes for a webpage to become interactive. A page is considered interactive when most of the user input receives a response (e.g., hovering over a link).

Why is First CPU Idle Important?

The First CPU Idle is important because it is taken into account when calculating your site's overall performance score. Your site's CPU idle time is compared with other sites' time in the HTTP archive in order to determine a percentile score. This along with several other metrics impacts your site's speed and performance.

How Can the First CPU Idle Be Improved?

Opportunities to improve your first CPU idle are usually found in the site's JavaScript. Optimizing your JavaScript code and removing any unnecessary JavaScript will improve your first CPU idle significantly.