Nvidia has unveiled its second-generation Tegra mobile system-on-chip processor, before the first generation has seen much traction (outside of the excellent Zune HD, Tegra hasn't really appeared in any marquee 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 available 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. The 3D graphics processor in Tegra 2 is architecturally similar to Tegra 1, but Nvidia expects about an increase in performance of 2-3x thanks to higher clock rates and improved memory bandwidth.
Tegra 2 also supports LPDDR2 (low-power DDR2) memory, while Tegra 1 only supports LPDDR1. This will mean a substantial increase in system-wide memory bandwidth.
Video decode and power efficiency are arguably the areas Nvidia is thumping its chest about most. The video decode block of Tegra 2 can smoothly decode 1080p H.264 high profile video at bitrates up to 10 megabits, and the company demoed this capability on a pre-production tablet at CES. This is claimed to be miles ahead of similar SoCs from other vendors. Flash video acceleration with Flash 10.1 is already up and running.
The power efficiency story is a little harder to judge. The claim from Nvidia is that Tegra 2 "delivers over 16 hours of HD video or 140 hours of music-on a single charge." Outside of saying that this test was done on a 5" tablet, no details are given. What resolution and bitrate video? What codec? Most importantly, how big was the battery in this test tablet?
Nvidia is initially promoting tablets with this new design rather than smartphones, and it's tempting to read a lot into this. Perhaps the tablet market is easier to enter, as tablets are being produced by more of the companies that Nvidia already has an excellent relationship with. Or, maybe the chip just costs too much for smartphone vendors. Perhaps the battery life isn't as great as they say when paired with a smaller smartphone battery? Or, it could be a matter of space - the Tegra 2 SoC is tiny and includes a lot of features, but it eschews cellular modems and Wi-Fi. My guess is that it has more to do with tablets being the "hot product" this year, along with the hi-def video capabilities being best suited, at this time, to a larger screen format.
Already Nvidia has a number of design wins for Tegra 2 based tablets, so we'll see those start to hit the market in the first half of this year. I wouldn't be surprised to see Tegra 1 and Tegra 2 based smartphones announced at the Mobile World Congress expo next month, too.