Surprise: the iPad 2 running iOS 4.3 is faster than the original iPad running iOS 4.2. According to CNET UK, which had the chance to run a JavaScript SunSpider benchmark test on the iPad 2 during a brief demo at San Francisco, the iPad 2 will outperform the competition and even other Apple’s devices when it comes to web browsing experience and overall snappiness of the browser application. The SunSpider test is usually a good test of how a browser will perform with “heavy” webpages with lots of content and functionalities such as Facebook.

Indeed, Apple itself promotes the new Nitro JavaScript engine that powers Safari on iOS 4.3 as “twice as fast” than its predecessor on iOS 4.2. The original iPad, however, also comes with a slower and non-dual core processor (Apple A4), whilst the iPad 2 will get a dual-core A5 and likely more RAM. These hardware features, together with the iOS 4.3, should make the device a lot faster than iPad 1, iPhone 4 and several Android tablets out in the market or coming soon.

Back to the SunSpider JavaScript test, CNET writes:

Incidentally, when you compare the iPad to the other devices we tested, Android phones and tablets don’t come out particularly well. The Galaxy Tab is more than 3x slower than the iPad 2 in this test, and about 2x slower than the original iPad with the new software. The Google Nexus S smart phone doesn’t fare too well either, at nearly 3x slower than the iPad 2. There’s really good news for iPhone 4 owners out there: when it arrives, iOS 4.3 will deliver a 2.5x speed increase in this test.

The one device we’d like to test, but can’t, is the Motorola Xoom. This tablet has a dual-core processor and runs the latest version of Android, 3.0 Honeycomb.

We will get our iPad 2’s next week and we’ll make sure to run some tests as well to see how the new tablet is really faster than other devices with iOS 4.3 and the iPad 1.