As we, presumably, get close to NVIDIA's quad-core Tegra SoC - codenamed Kal-El - finally making a public appearance, NVIDIA is starting to trickle out a few more details about what gives the chip its mojo.
The four ARM Cortex A9 CPU cores will, in theory, give Kal-El a performance advantage over its competitors, none of which are expected to hit quad-core until well into next year. How much of an advantage is hotly debated, not least by Qualcomm, with many questioning whether four cores can be properly utilized and what the power implications are.
Unperturbed, NVIDIA has now announced there is a fifth CPU core in Kal-El, which is also a Cortex A9, but is manufactured on a low power silicon process. This means it's optimised to work on simpler tasks while using very little power in so doing, in fact its maximum clock is limited to 500 MHz.
NVIDIA is calling this the companion core, and goes into much greater detail on the matter in a white-paper that you can read for yourself here. In essence it enables an ‘active standby mode', in which a device sporting this chip is still able to do background tasks, such as downloading email and alerts, while in a very low power state.
In the white-paper NVIDIA also discloses a new type of technology called Variable Symmetric Multiprocessing (vSMP), of which the companion core is central. Apparently this technology makes the companion core platform agnostic, meaning software automatically takes advantage of it without the need for special coding, which is nice.
The two images below convey the basic concept, should you not be in a very white-paper place right now. If you are, you might want to double up and read this one on why quad-core is great for mobile devices. This was no doubt produced to counter the FUD being disseminated by the likes of Qualcomm on the matter.