Chrome 41 shipped with several optimizations to make the visual experience of loading sites faster (Speed Index, Start Render, etc). The most impactful of the changes was to have the main parser conditionally let pending paints and layouts happen before going into execute a script.
In practice this means that before running scripts at the end of a page it will do the layout and paint for whatever it has built up so far (assuming it is not waiting for css). It doesn't change the classic technical metrics (Page Load Time, DOM Content Loaded, etc) but it can have a huge benefit to more visual-based metrics, particularly first paint/start render and Speed Index (and more importantly, on when users can see progress and start consuming the page content).
A nice side-effect is that it also improves performance for things like custom fonts and prioritization of above-the-fold resources, both of which depend on layout and styles being applied before they can be discovered by Chrome.
Here are some sample filmstrips with before/after comparisons demonstrating the impact (you may need to zoom in on some of the longer filmstrips to see them).
As always, your mileage may vary and not all sites will see the same magnitude of improvement (if any).