Of course, if we want to opt out of these features entirely, there’s always text-rendering: optimizeSpeed, which does away with optimizeLegibility’s features—and costs—entirely, no matter the type size. I’m almost always willing to defer to the browser by keeping the default text-rendering: auto intact, but if you find yourself working on a page with a healthy amount of text with a font-size larger than 20px, you may want to finesse things a little with text-rendering: optimizeSpeed.
http://bocoup.com/weblog/text-rendering/
