Game engine legend John Carmack tweeted that NVIDIA's Tegra K1 performance claims should be taken with several grains of salt.
In its marketing slides, NVIDIA claims the Tegra K1 offers much greater graphics power than the Xbox 360 and PS3 but Carmack clearly doesn't seem to believe this:
Take Nvidia's comparisons between their K1 SoC and consoles with several grains of salt.
That’s a fairly strong statement for a developer to make, particularly one with Carmack’s influence. So what, exactly, has Nvidia said? The Tegra K1 whitepaper states that “A vast majority of Xbox 360 and PS3 titles could be easily ported to Tegra K1 devices with minimal effort, delivering similar visual quality and gameplay experience.”