While the pre-release build of iPhone OS 2.0, officially available only to select developers and beta testers, is sluggish and buggy overall, one area of operation has seen a dramatic performance boost. The new version of Safari included with iPhone OS 2.0 is up to 35 percent faster at executing JavaScript than previous editions of the iPhone OS.
Prior testing of iPhone OS 1.x's JavaScript performance using Celtic Kane's benchmarks revealed performance 30 times slower than that of a 1.83 GHz MacBook Pro, with iPhone-generated test times in excess of 9000 ms on average. Under iPhone OS 2.0, however, Celtic Kane's benchmarks run the gamut in just over 6000 ms.