Android phones whisk users across the web in two-thirds the time that the iPhone takes, according to a study that compared the two top mobile OSes' performance when downloading web pages.

(See update below for caveats about the study, and Apple's rebuttal.)

The study, conducted by mobile-website–optimization company Blaze.io, involved more than 40,000 downloads of web pages belonging to the Fortune 1000 companies. The iPhone took 52 percent longer than Android to render full web pages. On average, Android phones took 2.1 seconds to render non–mobile-optimized web pages, while the iPhone took 3.2 seconds.

Android bested the iPhone on site-loading time a whopping 84 percent of the time.

The test included the Samsung Nexus S (Android 2.3), Samsung Galaxy S (Android 2.2), iPhone 4 (iOS 4.3) and iPhone 4 (iOS 4.2). Pages were loaded using a strong Wi-Fi connection, and each device loaded each Fortune 1000 website three times.

Oddly, the study found that the much-touted JavaScript improvements in the latest versions of Android and the iPhone had little real-world effect on these web pages.

"Our conclusion is that JavaScript performance doesn’t impact an average page load time," the company wrote in the study. "Apparently, JavaScript is already so optimized that it doesn’t play a big role in the time it takes to load a page. It’s likely that rich AJAX applications benefit from these improvements, but users should not expect their casual web surfing to move faster."

UPDATE Thursday 1:00 PM PST: Blaze is investigating whether the app they used to test page load times actually takes advantage of Apple's Nitro JavaScript engine.

"We’re still investigating this issue, as the report was completed before it was made known. So far we’ve seen indications in both directions, so we can’t say for sure it’s being applied.

That said, the results from measuring Android show that JavaScript only accounts for a small percentage of the total load time, about 15% on average. This implies that even if Nitro is not in use, it likely can only slightly narrow the gap."

Apple says the test is flawed because web apps on the iPhone can't currently use the Nitro engine included in the iOS 4.3 update, which recently caused controversy among web developers who accuse the company of intentionally handicapping web apps in order to promote those specifically written for iOS.

"Blaze's testing is flawed because it didn't test the Safari web browser," Apple spokeswoman Trudy Muller told Wired.com Thursday. "They were only testing their own proprietary web app that doesn't take advantage of Safari's web optimization." /UPDATE

Both OSes clocked in nearly identical 2-second loading times for pages designed especially for mobile devices.

The company says the results surprised them.

We assumed that similar hardware specs and the same WebKit foundation would make iPhone and Android’s browsers perform equally. We assumed that a faster JavaScript engine equals a faster browser. We assumed that 3G would be way slower than WiFi, even under good conditions.

All of these assumptions have been proven wrong when we actually measured those scenarios. Without measuring, you don’t know when and where you need to optimize.

The Android-vs-iPhone-F1000-Paper includes more details on Blaze's methodology and conclusions and will definitely be required reading for the ongoing battle between Android and iPhone fanatics.

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