Sunspider Javascript Benchmark
I ran the Sunspider javascript benchmark on both devices. While the benchmark is quite dependent on browser performance, it is also an indicator of CPU ability, as well as a cross-platform benchmark, allowing us to compare both the iPhone 4 and Droid X from a more objective perspective. I used the default browser on each phone for the test.
On average, the iPhone 4 was 1.3x as fast the Droid X (click to view detailed test results):
(smaller ms is better)
Droid X – Total: 13,511.2 ms +/- 1.2%
iPhone 4 – Total: 10,401.4 ms +/- 1%
I also gave the Sunspider benchmark a try using a different browser than Android’s default. I used Dolphin Browser HD to run the test and actually resulted in a slower score (around 16,000 ms).