&gt; The lack of a before&#x2F;after demo.<p>See the graphs here: <a href="https:&#x2F;&#x2F;www.phoronix.com&#x2F;scan.php?page=news_item&amp;px=MTgzNDA" rel="nofollow">https:&#x2F;&#x2F;www.phoronix.com&#x2F;scan.php?page=news_item&amp;px=MTgzNDA</a><p>We also have various real-world performance demos showing that, for certain workloads, parallelism results in measurable FPS wins. I haven&#x27;t wanted to get on stage and publicize them at this point, because it&#x27;s early. But we do have them.<p>&gt; What, specifically, were the performance goals then?<p>I wasn&#x27;t involved with the design of flexbox, but I didn&#x27;t see performance as the main goal. Rather, the goal was to make &quot;springs and struts&quot;-style UI layout easy to use, because simulating it in CSS2 had bad ergonomics. Performance wins, if anything, would be relative to doing all of the layout manually in JavaScript, not relative to the CSS2 primitives.<p>Historically, relatively little attention has been paid to <i>layout</i> performance at all. The main performance wars have concerned DOM performance and JavaScript. (Look at what Dromaeo tests, for example.)<p>&gt; Link?<p>I don&#x27;t have time to create an actual demo for the specific thing you&#x27;re asking for, but I&#x27;ve done many similar tests. Animating transforms will achieve 60FPS.