According to Anandtech, the iPhone 5's A6 running dual ARM cores runs the fastest SunSpider test ever for a smartphone. That SunSpider test measures Javascript performance which runs in web browsers. The results prove out that the speeds reached by the iPhone 5 are faster even than those achieved with Intel's Atom z2460 chips.
As the graphic below shows, the vaunted Samsung Galaxy III S runs at 1824.9 (roughly the same as the iPhone 4S), which is half the speed of the iPhone 5, which clocked in at 914.7.
