20ms was just to say "not a whole lot" - all the small differences amount to nearly as much as when you have dedicated benchmarks showing how Firefox is particularly slow in certain aspects. I tried Chrome for a few weeks recently and the only two things it did noticably better was UI smoothness and web apps like Google Maps. Other than that I was mostly annoyed at many little things that I couldn't adjust, like forcing "new window" links to open in the current tab. And the extensions barely deserve to be called that.
It's nice if Chrome suits you, but get off that high horse.