Many mobile users of your page experience the equivalent of a 3G network connection. Ensuring that your page loads fast over a simulated 3G network ensures that your page loads in a reasonable amount of time for your mobile users.
There are two main metrics regarding how users perceive load time:
- The page appears visually complete.
- The page is interactive. If a page appears visually complete at 1s, but the user can't interact with it until 10s, then the perceived page load time is 10s.
Lighthouse throttles the page if the network connection is faster than 3G and then measures the time to first interactive. If the time to first interactive is less than 10s, the audit passes.