So, what exactly is Tegra? It's an ARM-based system-on-a-chip design, with an ARM11 750Mhz processor. The entire SoC seems to be geared towards multimedia processing, as it allows for full HD (1080p) playback, both on the internal display as well as an external one. The GPU also accelerates processing of Flash content, and since slowness in Flash on Atom-based devices is pretty common, this can only be seen as a good thing (we'll ignore the fact that Flash is a pile of crap and should not need GPU acceleration in the first place, but let's not go there again).
This being ARM-based equipment, battery life is mind-blowing (again, if we were to believe NVIDIA): 25 days of music or 10-hours of 1080p video playback on a single charge. Let me repeat that for you: 25 days of music or 10-hours of 1080p video playback on a single charge. Seeing an Atom-based device barely pulls a few hours of normal usage (and does not allow for HD playback at all), this is pretty amazing stuff. NVIDIA also promises that "video games play at up to 46 frames per second", but on whatever game that's based, I don't know. Furthermore, the processor is "always-on", meaning you'll get instant access to your network (cool). 3G, WiFi, and WiMax are all supported.
That's the hardware side of things - what about software? This is an ARM-based design, so regular Windows won't work. That means Linux, right? Well, of course, Linux will work. However, the first actual working device based on this new Tegra 650 platform runs... Windows CE. It's called the Mobinnova élan smartbook, and comes with a custom 3D-ish interface designed by NVIDIA. A short video below, where it plays a 1080p trailer.
Devices based on this new Tegra 650 platform will arrive before the end of the year, at USD 199, but they could be as cheap as USD 99 if subsidised by mobile carriers.