Just how much faster is the iPhone 3GS?

In case you haven’t got it yet, the ‘S’ in iPhone 3GS stands for ‘speed’. (And yes, the name of the uberphone has been changed from ‘3G S’ to ‘3GS’ at the imperial command of His Jobsness, at least according to Boy Genius Reports.)

And since last week’s US debut of the 3GS we’ve seen no end of speed tests against its predecessor. But how much of that improvement is due to the new iPhone 3.0 operating system, which can be applied to any iPhone 3G?

And if the OS alone provides a serious speed boost, might owners of the iPhone 3G be happy to stick with their updated smartphone rather than splash their cash on the shiny new 3GS.

US mobile advertising and analytics firm Medialets has conducted a direct comparison between the Javascript performance of an iPhone 3G running OS 2.2.1, another iPhone 3G upgraded with OS 3.0, and a factory-fresh iPhone 3GS.

The tests rely on the SunSpider JavaScript test suite, which Medialets says “we have found to be one of the best attempts to measure real world JavaScript performance in a balanced and statistically sound way.”
The results pretty much speak for themselves – just applying the free iPhone 3.0 update to your existing iPhone 3G yields a nearly 3x turbo-charge to JavaScript performance. So if a handy speed kick is what you crave most for your iPhone, upgrading to OS 3.0 could be a cheap and cheerful fix.

However, the hardware in the iPhone 3GS further triples the impressive score of OS 3.0.

Medialets also applied the same tests to the T-Mobile’s G1 (aka HTC Dream) running Android 1.5 ‘Cupcake’ and the Palm Pre, as both these devices use browsers built around the open source WebKit project.

To the delight of Apple fanboys, the iPhone 3GS leaves these competitors eating its digital dust. The Palm Pre is no faster than the updated iPhone 3G while the G1/Dream is almost twice as slow again, and five times slower than the iPhone 3GS.