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LG Preparing A72-Based NUCLUN 2 Processor

August 13, 2015 - Written By David Steele

LG are preparing a new System-on-Chip, based around the ARM reference Cortex-A53 and Cortex-A72 cores plus an Intel modem for high speed 4G LTE networking, which is due to enter production next year. Today’s story concerns that pre-production benchmark figures have been spotted on the social network Weibo, showing that the new LG chipset is more powerful than the current Samsung Exynos 7420, which is considered to represent the current high mark for mobile System-on-Chips. The benchmark scores showed the Exynos 7420 as scoring 1,486 in the single core benchmark and 4,970 in the multi-core benchmark, with LG’s new NUCLUN 2 SoC scoring 1,796 in the single core benchmark and 5,392 in the multi-core benchmark. We have seen articles claiming that Qualcomm’s next generation Snapdragon 620 and 820 chips benchmark only slightly higher than the Exynos, but these do somewhat miss the point, which is that most benchmark scores are little more than an abstract metric that showed how one particular hardware rig was able to complete a predetermined number of tasks quicker than a hardware rig sat next to it. We cannot always determine “real world” performance from these cold, harsh statistics.

LG’s new processor is a reasonably traditional sounding chipset, based around two quad core clusters of application cores arranged in a conventional big.LITTLE design. The lesser cluster is based around the ARM Cortex-A53 core, which is a low powered, 64-bit application process optimized for battery efficiency. The higher powered core consists of the ARM Cortex-A72 core, ARM’s replacement for the Cortex-A57 core. We have detailed the Cortex-A72 elsewhere but it is designed to be more powerful and more efficient than the Cortex-A57. It’s built at the 16nm process size, compared with the Exynos’ 14nm size. The smaller the process, the lower the voltage needed to drive the chip and so the lower the power used and heat produced. Being more powerful in isolation is nice, but as we have seen with the Qualcomm Snapdragon 810, being powerful is not enough: a processor also needs to moderate its heat output, so that it can continue to process information quickly over a period of time rather than in bursts. Here, the Cortex-A72’s improved performance and efficiency should result in cooler temperatures for the same workload, or higher performance for the same temperatures. Although the NUCLUN 2 is built on a slightly larger process compared with the Exynos, it uses a newer generation processor architecture and so should be reasonably expected to outperform the Samsung Exynos 7420.

The wildcard here is how well Qualcomm’s custom core, called Kyro, will perform. You see, the Samsung Exynos and LG NUCLUN, plus numerous other chips including the MediaTek Helio X20, use off-the-shelf ARM core designs. For years, Qualcomm have designed their own processor cores and imbued them with their own “special sauce.” The Qualcomm Snapdragon 820 will be based around their new 64-bit custom core, Kyro. It is reputed to dispense with the big.LITTLE approach and instead uses a quad core arrangement. It remains to be seen how Qualcomm’s Kyro handles the heat and the difference between bursty performance and sustained load.