OS X Mountain Lion (10.8.2)
After receiving numerous conflicting results from readers with genuine Macs, it has come to our attention that our current cross-platform test system provides unusually low browser scores under OS X. After several different networking driver swaps, the scores remain quite low compared to other operating systems. While the OS X browser scores appear to be accurate in relation to each other, none of the OS X scores should be used to draw conclusions about OS X versus other environments in this test. Our previous Core i5 (Lynnfield)-based cross-platform test system did not exhibit this behavior, but actually showed browsers under OS X performing better than Windows 7-based browsers on the Hackintosh than on a genuine MacBook Air. So, until we can track down the culprit, please view the OS X results as if they were obtained on different hardware than the other OSes.
Safari 6 takes first place with ease on OS X, maintaining a cool 14% lead over second-place finisher Google Chrome. Trailing an appropriate 21% behind Chrome 21 is Firefox 15. Opera 12 places last in RoboHornet on OS X, another 15 percentage points behind Firefox, roughly half of Safari's winning score.
Things are looking good for RoboHornet on OS X; this finishing order closely mirrors our results from Web Browser Grand Prix: Firefox 15, Safari 6, OS X Mountain Lion.