Myth: Lighthouse 100 means a fast site

Myth: Lighthouse 100 means a fast site
Lab score 100 -> field p75 LCP 3.4s. The two aren't the same measurement.
Lighthouse is lab (synthetic, one cold load, throttled to a fixed Moto G profile). CrUX field data is p75 of real users across networks, devices, cache states.
— A 100 lab score with a single slow-3G user segment still fails Core Web Vitals.
— We've audited sites at lab 98 sitting at field LCP 4.1s because the lab run cached the hero image; real first-time visitors didn't.
Measure the thing Google ranks on: field p75, not lab.
Takeaway: the number that matters is field p75 LCP, not the lab gauge.