Our Test Agents are now using Chrome 131 and Lighthouse 12.3.0 to test your Sites. You can find details surrounding the 12.3.0 release in the official Lighthouse changelog.
As part of this update, Lighthouse 12.3.0 includes a reduction in CPU throttling (introduced in Lighthouse 12.2.3) that affects Calibre’s PageSpeed Mobile Test Profile preset.
PageSpeed Mobile’s CPU throttling multiplier has been lowered from 1.5 to 1.2, which results in lower Total Blocking Time (TBT) measurements, higher Performance score and faster overall main thread activity.
It is expected that you will observe an improvement in performance metrics for PageSpeed Mobile following this change.
The CPU throttling update was made by the Lighthouse team to better reflect real-world device performance.