NVIDIA Tegra

NVIDIA Tegra is a system-on-a-chip (SoC) series for mobile computing devices. It is a heterogeneous processor architecture with multiple processors: CPU, a HD video processor, an imaging processor, an audio processor, and an ultra-low power GeForce GPU(See the article). For detail on Tegra architecture, see the whitepaper on NVIDIA® Tegra™ Multi-processor Architecture

Tegra2 series
It has a Dual-core ARM Cortex-A9 CPU (lacking ARMs advanced SIMD extension), ULP GeForce GPU with 4 pixel shaders + 4 vertex shaders (OpenGL ES 2.0), a single-channel memory controller (See the link), and 1080p video playback processor.

Project Kal-El
It has a quad-core CPU and a twelve-core GPU. It is five times faster than the Tegra2.
While searching information on the project, I found that an NVIDIA blog post states that it will have the fifth core. See the post.

NVIDIA Project Kal-El Demo: Glowball

Tegra Roadmap
The figure below shows NVIDIA's roadmap for its chipsets. The Stark chipset will be 75 times faster than the Tegra2. It's amazing.

Roadmap for Tegra series

Tegra development resources
NVIDIA provides all the resource for Tegra developers at http://developer.nvidia.com/node/19096