Apple has said that the third-generation iPad should equal the iPad 2 in battery life. However, PCWorld Labs battery-life tests show that, in a controlled environment, Apple's claims don't hold up: The new iPad lasted just 5 hours, 41 minutes, nearly 2 hours less than the iPad 2, which logged 7 hours, 37 minutes.
We conducted our tests while repeatedly playing a short video ("Big Buck Bunny" at 320 by 180 resolution, with a running time of 9 minutes, 56 seconds) on the iPad's built-in video player. We left Wi-Fi on and connected, and set the brightness to maximum; auto-brightness remained disabled.
The new iPad's score was better than what we've seen from many of the Android tablets we've tested, but it certainly wasn't comparable to the iPad 2's results. It was also a far cry from the all-day performance we had hoped to see. Apple estimates the battery life at up to 10 hours; the company says its estimates are based on mixed audio, video, and Web-browsing use, over Wi-Fi or cellular networks.
As you can see in the chart below, several noteworthy Android contenders surpass the new iPad in battery performance. The Asus Eee Pad Transformer Prime survived for 7 hours, 7 minutes, the Motorola Droid Xyboard 10.1 ran for 6 hours, 19 minutes, and the Samsung Galaxy Tab 10.1 Wi-Fi lasted for an extraordinary 10 hours, 42 minutes.
The new iPad's result is intriguing. One possible factor: The high-resolution, 2048-by-1536-pixel display on the new iPad is brighter than the 1024-by-768-pixel screen of the iPad 2. On a Minolta Luminance Meter LS-100, the new iPad's display registered a luminance of 434 candelas per square meter, to the iPad 2's 400 cd/m2.
How much of the new iPad's battery drain is attributable to its beefier processor and how much is due to the brighter, higher-resolution display is unclear. Our colleagues at Macworld performed battery-life tests at full brightness and at 150 cd/m2, and the new iPad consistently ran for a shorter period than the iPad 2 did. In Macworld's tests, the new iPad at full brightness ran for one-third less time than its predecessor did, lasting 5 hours, 40 minutes to the iPad 2's 8 hours, 30 minutes. At 150 cd/m2, the difference was a bit smaller, but still significant--the new iPad's battery lasted 10 hours, 10 minutes, versus the iPad 2's running time of 13 hours, 20 minutes.
It's also unclear whether Apple may be having battery-management problems with the third-gen iPad that go deeper than the charging issues we've seen, including the tablet's failure to charge while in use, and its showing a full charge when it may still need additional juice (as some reports have indicated, but Macworld's testing didn't show).
What is unmistakable, however, is a 25 percent decline in battery performance in our tests from the iPad 2 to the new iPad--and this is something we hope Apple will investigate further and address through software updates.