NVIDIA Kal-El quad-core platform to include a stealthy power-saving fifth core
By Pawel Piejko
September 21, 2011
NVIDIA promised us back in May that its Kal-El Project quad-core system-on-a-chip platform for mobile devices would come as a "battery-friendly" solution, although without giving details at the time. The company has recently outlined the secret behind Kal-El's energy efficiency - it's a technology called Variable Symmetric Multiprocessing (vSMP), which is based on an extra fifth "companion core" designed to perform less demanding tasks in the background.
Most mobile devices rest in "active standby" mode for 80 percent of time, while intensive tasks cover about 20 percent, NVIDIA says. During active standby mode, however, numerous tasks are still happening in the background - e-mail syncs, social media syncs, live wallpapers, active widgets, etc. That's where the fifth core comes into action.
Described in NVIDIA's recently published document, the patented fifth core is also ARM Cortex A9-based, but comes clocked at a lower frequency than the main performance cores, running at up to 500MHz and operating at very low power. Thus, the processing comes courtesy of a companion core during standby mode or less power-hungry tasks, such as web reading, music playback and video playback.
When a more demanding task is initiated, Kal-El automatically turns off the companion core, replacing it with main, performance cores which are individually enabled and disabled depending on the intensity of workload. NVIDIA also describes vSMP architecture as transparent, since operating systems and applications don't need to be redesigned to utilize the fifth core.
Power savings due to vSMP architecture in comparison to the Tegra 2 dual-core platform are up to 61 percent during HD video playback, 34 percent while gaming, or 14 percent during MP3 playback.
Also referred to as Tegra 3, Kal-El is a new system-on-a-chip platform for portable devices being developed by NVIDIA. It features four ARM Cortex A9 CPUs running at up to 1.5GHz built in 40nm standard silicon process, and a fifth core (kept secret until now) built using a special low power silicon process. There's also a new 12-core GPU with 3D stereo support. Previously expected to be released in August, Kal-El is now rumored to be available this year in at least one tablet, while Kal-El-equipped smartphones are due out in 2012.