Mike Rayfield of Nvidia mobile business unit, said Nvidia preferred Microsoft's Windows CE over Android because of CE's maturity. He said Android currently has a rough user interface. For smartbooks, Nvidia is working with Microsoft to optimize Windows CE when it runs on Tegra. The counterpart to Nvidia's Ion platform for Intel Atom-based netbooks, Tegra bundles an ARM CPU (the 750 MHz ARM 11) with specialized chips designed by Nvidia for graphics, HD video encoding and decoding, stereo sound and more. That will allow Windows CE devices to offload much of the heavy multimedia work onto Tegra, resulting in better performance, 1080p video, and low power usage. Nvidia claims that Tegra smartbooks should allow users to listen to music for 25 days or watch HD video for 10 hours, versus 5 hours and 3 hours, respectively, for an Intel Atom netbook.
More info: Computerworld