What's the difference between the iPad and iPad 2?

From a purely physical standpoint, there are a few subtle -- yet very significant -- differences between the first- and second-generationiPads. For starters, the iPad 2 is thinner and lighter than its predecessor. The new version of the tablet is about 8.8 millimeters thick, about 33 percent thinner than the original iPad. And at a weight of between 1.33 and 1.35 pounds, depending on model, the iPad 2 can be up to 15 percent lighter than the iPad.

The weight and thickness differences may not matter to many users -- the original iPad is still a fraction of the size of laptop computers and has a larger screen than many competing tablet devices. Likewise, the option of getting an iPad 2 with a white case instead of the original iPad's standard black may not sway more than a few very fashion-conscious buyers. But another addition to the iPad 2 could play a big role in your decision as to which iPad to purchase.

One of the criticisms leveled at the first iPad was that it lacked a user-facing camera. This seemed to defeat one potential use for tablets: real-time videoconferencing. Apple addressed this issue by adding both forward- and backward-facing cameras on the iPad 2. If you intend to use your iPad as a communication device, making and receiving calls or using it as a virtual tool to plug into remote meetings, this could be an important physical feature to consider.

主要的difference between the iPad models comes not in physical form, but in computing performance. While both models offer storage capacities of 16, 32 or 64 GB, the iPad 2 increases processing power with 512 MB ofRAM, versus the iPad's 256 MB. Likewise, while both iPads offer 1 GHz processors, the iPad 2 uses a dual-core A5 chip, versus the iPad's A4 model.

This translates into faster functionality for the iPad 2. Games may play better, and multimedia applications, like the aforementioned videoconferencing, will run smoother and with less likelihood of processor hang-ups.

The iPad 2 also includes tools that take better advantage of the tablet computer's mobility. A three-axis gyro sensor in the tablet senses changes in position, meaning that games and applications dependent on moving the device will work with much more precision than before. Even though the 3G versions of both iPads come with built-in GPS capabilities, the addition of the gyro to the iPad 2 means place- and position-based applications will be more useable and precise on it than on its forebear [source:Aamoth].