Nvidia's next-generation Tegra processor, codenamed "Project Kal-El," is widely known as the world?s first quad-core mobile chip. However, Nvidia today unveiled Kal-El?s little-known fifth core.
The Project Kal-El processor implements the new Variable SMP
architecture technology. vSMP inludes a fifth core built using a low
power silicon process, it runs at a lower frequency and operates at low
power. During less power-hungry tasks like web reading, music playback
and video playback, Kal-El completely powers down its four
performance-tuned cores and instead uses its fifth companion core. For
higher performance tasks, Kal-El disables its companion core and turns
on its four performance cores, one at a time, as the work load
increases.
In addition to four main Cortex A9 high-performance CPU cores, a fifth
low power, low leakage Cortex A9 CPU core is optimized to minimize
active standby state power consumption and handle less demanding
processing tasks.
Power performance measurements released by Nvidia on Kal-El show that
the fifth core delivers higher performance per watt than the main cores
at operating frequencies below 500 MHz.
vSMP is also completely OS transparent, which means that operating
systems and applications don't need to be redesigned to take advantage
of the fifth core.
When the Companion core is turned off and the mobile processor using
main cores for processing, the CPU Governor and CPU management logic
continues to monitor workload and utilization of each the main cores,
dynamically enabling or disabling one to four of the main cores.
Of course, the vSMP technology does not allow both the fifth core and
the main cores to be enabled at the same time. The fifth core and the
main cores also share the same L2 cache, Nvidia said.
Nvidia also claims that quad-core Kal-El uses less power than dual-core
processors across all performance points.
Nvidia's results from Moonbat, a Web based JavaScript benchmark, show
that a quad core CPU delivers almost fifty percent faster Web browsing
performance compared to dual core CPU based mobile processors.
Project Kal-El also includes a new 12-core GPU that delivers up to 3x
the graphics performance of Tegra 2, as well as several additional new
capabilities, according to Nvidia.
The graph below shows the performance speedup that the quad core CPU
based Project Kal-El platform provides for the Glowball demo over an
equivalent dual core CPU based platform.
Handbrake, a popular video transcoding application, delivers faster
transcoding on a quad core CPU system compared to a dual core system.
The 40nm Kal-El is expected to hit tablets in late 2011 and early 2012.