updated 03:10 pm EST, Wed March 9, 2011
We bench iOS 4.3 in SunSpider
The iOS 4.2.1 test was, to put it mildly, slow. At 8,217.5ms to complete the test, it was not only slower than most Android phones but felt slow to run: some tests, such as the 3D and string tests, took well over a second to complete. When you're loading a website, adding a few seconds just adds to the perceived slowdown.
In iOS 4.3 tests, the results were dramatic: only the string test took any longer than half a second, and it shaved about 0.6 seconds off what was previously a very long time. The subjective difference was large enough that we were willing to see the test complete with the iPad in our hands in iOS 4.3 where we'd set the iPad down for a break waiting for 4.2.1 to finish.
How does the iPad 2 fare? While we won't know for certain until the iPad 2 ships, early tests have given a score of 2127.2ms, or about 34 percent faster than what we saw today. The result might disappoint those who were expecting the iPad 2 to match Apple's "twice as fast" claims in every case, but it's likely dictated by other factors as well; we don't know how optimized Safari is for dual-core processors or graphics acceleration, for example.
As such, the iPad 2 won't make a dramatic difference over a 4.3-upgraded iPad unless you spend all your time in complex web apps. However, it's clear that 4.3 is not just a virtually necessary update and, from what we've seen, should outperform the current Android phones and tablets that outran iPads using iOS 4.2.