In January Nvidia launched its Tegra 4 ‘Wayne’ SoC, a high-end ARM processor with four Cortex-A15 cores and a 72-core GPU. The Tegra 4 is Nvidia’s new high-end ARM chip, made for ‘super phones’ and tablets. The Tegra 4 does appear to be an expensive and power-hungry chip, so in order to complement its flagship chip Nvidia today presented the Tegra 4i. Previously known as 'Gray', the Tegra 4i is a smaller and more energy-efficient chip that is set for release at the end of 2013. Nvidia claims it will make high performance possible in affordable smartphones.
ARM Cortex-A9 R4
Like the Tegra 4, the Tegra 4i is a 28 nanometer chip, but smaller. That's because the Tegra 4i doesn't have the Cortex-A15 cores of the Tegra 4, but revised Cortex-A9 cores. Nvidia claims it's improved the Cortex-A9 design, presented the changes to ARM, which then was integrated into the fourth revision of the Cortex-A9 core.
Unlike previous revisions that only introduced minor improvements, this last revision should be 15 to 30 percent faster at the same clock speed than the previous one. The cores in the Tegra 4i run at an unprecedented clock speed of 2.3 GHz, and Nvidia claims the CPU speed is in fact twice as high as that of the Tegra 3. It's the first SoC to feature the new R4 version of the Cortex-A9, but other manufacturers are also able to license the new revision. The Tegra 4i also has a fifth energy-efficient core that takes over when only little power is required.
Nvidia Tegra 4i die-shot
So the CPU is different in the Tegra 4i compared to the Tegra 4, and the same is true for the GPU. The Tegra 4i has only 60 GPU cores compared to the 72 GPU cores of the Tegra 4. Whether the GPU cores are the same hardware-wise is unclear, and Nvidia hasn't specified anything yet about the memory interface on the new chip.