Nvidia has unveiled its second-generation Tegra mobile system-on-chip processor, before the first generation has seen much traction (outside of the excellet Zune HD, Tegra hasn't really appeared in any marqee products).

So what's new in Tegra 2? A faster ARM processor and better graphics and video, while still emphasizing extreme power efficiency.
Tegra 2 upgrades the ARM11 CPUs in the original chip to the ARM Cortex A9. The Cortex A9 is avilable with up to 4 cores, but Tegra 2 ships with a dual-core version.
This is a substantial improvement - the Cortex A9 is an out-of-order speculative superscalar processor that offers 2.5 Dhrystone MIPS per core at speeds up to 1GHz.
It's safe to say it's several times faster than the ARM11 cores in the original Tegra, and a significant step up from even the Cortex A8 found in products like the iPhone 3GS.
As with the first-generation Tegra chips, Tegra 2 features a bunch of individual processing cores on a single chip, each of which can be turned off or scaled back to carefully manage power consumption.
There's an audio processing core, a 2D/3D graphics processor, an HD video decoding processor (capable of smooth 1080p playback), an HD video encoding block, an audio processor, and a still image processor.
It's unknown how well the 3D graphics stacks up with the latest PowerVR-based graphics cores.
(Source: PC World)