How fast is headless vs. normal? According to https://developers.google.com/web/fundamentals/performance/critical-rendering-path/render-tree-construction https

How fast is headless vs. normal? According to https://developers.google.com/web/fundamentals/performance/critical-rendering-path/render-tree-construction https://developers.google.com/web/fundamentals/performance/c... the chrome browser spends a decent amount of time on other steps such as parsing HTML. I wonder how much time could be saved by not rendering pages into pixels.