First CPU Idle

Former called First Interactive, First CPU Idle measures when the page is minimally interactive, according to Google. This occurs when UI elements become active.

Oftentimes, sites that focus on visuals do so at the expense of user input which can hinder user experience and page load.

Improving this score

Optimizing critical rendering path by reducing the number of critical resources to be downloaded or used can help reduce load speed. When that is exhausted, work to minimize the remaining resources or files.