Nvidia Tegra 2
The dual-core Tegra 2 chip has one purpose: to give Android tablets and phones more battery life (up to an entire day) without sacrificing power. The processor draws just a tenth the juice used by its predecessors while still smoothly rendering high-def video.
To save power, the chip divides tasks—video encode and decode, image processing and audio—among groups of transistors, and it activates those areas only when it needs them. Tablets from $330