Last month we brought you a surprising story about the iPad 2. While most Apple products get a price reduction with the launch of their next-generation successor, one thing they don’t get is a hardware upgrade. It turned out, though, that with the launch of the new iPad the iPad 2 got a processor upgrade.

The iPad 2’s new processor, which is the same as the processor found in the third-generation Apple TV, is effectively the same as the A5 chip that was originally in the iPad 2 (and iPhone 4S). The difference is that it has been “ported” to Samsung’s new 32nm HMKG manufacturing process. As such, the chip’s performance isn’t greatly effective. That is, the 32nm chip isn’t faster than the original version. The big difference is an increase in energy efficiency. At the time, there was speculation that iPad users might see an improvement in battery life.

Now AnandTech has confirmed that that is the case. The updated iPad 2 does show an improvement in battery life. According to AnandTech’s tests, the updated iPad 2 performed better than both the original iPad 2 and the new iPad when playing a graphics- and power-intensive game – Infinity Blade II. While the new iPad lasted for 5.58 hours, the updated iPad 2 lasted nearly 8 hours.

(A quick note on terminology: “iPad 2,4” is Apple’s official model designation for the updated iPad 2. The iPad 2,1 is the wi-fi only model of the original iPad 2. The iPad 2,2 and iPad 2,3 are the AT&T and Verizon 3G models, respectively.)

The iPad 2,4 showed similar results during a lower-intensity game. They also tested video playback capabilities. To test the various iPads, they took a 720p High Profile H.264 video of Harry Potter and the Deathly Hallows. Removing the credits gave the movie a run time of exactly one hour and fifty-eight minutes. The movie was played in a loop until each tablet died. The iPad 2,4 beat the iPad 3 by over four hours, and the original iPad 2 by over two hours.

The iPad 2,4 gets a performance boost in another area, too. You may recall a bit of controversy surrounding the new iPad shortly after its launch in mid-March. There were reports that the tablet got excessively hot, though that turned out to be a common tablet problem, not just an iPad problem. Well, it looks like the iPad 2,4 beats both its predecessor and successor in this department as well. After an hour of playing Infinity Blade II, the iPad 2,4 was a full degree (Celsius) cooler that the original iPad 2, and almost nine degrees cooler than the new iPad.

With all the performance enhancements that come with the iPad 2,4’s updated processor, you might be inclined to go out and get one instead of a new iPad. The iPad 2, after all, starts at only $399. Unfortunately, it’s not quite as simple as walking into an Apple Store or any other retailer and just picking one of these up off the shelf. For one thing, there is no discernable difference between an iPad 2,4 and an iPad 2,1-3. From the outside the tablets themselves are identical, and the boxes are identical. Nor does there appear to be any difference in model number or any other feature you might be able to access before you buy one. In fact, the only way to be sure – apart from running one of these tests – is installing a utility like Geekbench and having it check for the actual model number of the device.

What’s more, AnandTech made several attempts to get their hands on these new iPads, and only came up with the one they used for testing, which suggests that there aren’t all that many of these in circulation.

Would you consider getting an iPad 2 instead of a new iPad if it meant you could get the enhanced processor?