Details are starting to emerge about the chip powering Apple's iPad - the A4. As it turns out, it's not a CPU but a complete 'system-on-a-chip.'
The A4 represents Apple's entry into fabless semiconductors, and while it's seems like interesting technology, most of it is based on ARM intellectual property. The A4 brings together a CPU (at this point it's unclear how many cores the A4 has) and a GPU, along with other features such as memory controller.
Compared to the Samsung processor in the iPhone that chugs along at 600MHz, the A4 ticks at 1GHz, offering the iPad a fair performance boost. Not only is it fast, but it's energy efficient, allowing the iPad to run for up to 10 hours.