How does it work?
The two ARM Cortex A9 cores deal with general-purpose computing, including web browsing and Java apps, while the ARM 7 processor (which is less power-hungry than the Cortex A9 ones) handles system management tasks, including NVIDIA's own power management technology.
The GPU deals with gaming and 3D user interfaces, while the dedicated video decode processor uses all kinds of intimidating technologies to deliver full frame-rate 1080p video and the video encoder allows 1080p recording. Lastly the image signal processor handles photography and the audio processor does what it says on the tin.
All of these cores are power managed such that only the ones doing the work at a given time are drawing power. The table below shows the kind of battery life NVIDIA reckons you can expect from a tablet running Tegra 2 in a few different usage models. This tablet has a 2000 mAh battery and a 400 mW display.
Not mentioned is the NVIDIA claim that Tegra 2 can manage 60 fps on Quake 3 at 1024x600. So we can expect to see PC games ported onto Tegra 2 tablets/slates, and don't forget it supports Adobe Flash too.
Apple claims ten hours battery life when watching video on the iPad, which has a 1024x768 screen and a 25 Wh battery. It's hard to compare the two batteries without knowing their voltage, but with the premise that you multiply amps by volts to get Watts, the NVIDIA battery would have to run at 12.5 volts to be equivalent to the Apple one, which seems unlikely.
Anyway, the long and short of it is that a slate running Tegra 2 should provide a superior graphics and video experience to the iPad, without much of a battery-life hit. As ever, we'll confirm this for ourselves when we get our hands on one, and we expect to see Tegra 2 tablets/slates start to appear in Q3.