Cortex-A35 Is ARM's Most Efficient CPU Core, Will Ship By End Of 2016

ARM introduced its next-generation high-efficiency mobile CPU core and the successor to the Cortex-A7 and Cortex-A53, the Cortex-A35. The company said the new CPU is the most efficient processor it has in its lineup right now, using 10 percent less power than its previously most efficient CPU, the re-baselined Cortex-A7.

ARM stated that the Cortex-A35 is also 25 percent more efficient than the Cortex-A53 core, which was known to be more power hungry than the Cortex-A7. It's also 25 percent smaller, which should be a boon to low-cost smartphone manufacturers.

The Cortex-A35 pipeline was redesigned for maximum efficiency, but it has remained an 8-stage pipeline with limited dual-issue capability. The new CPU also has a redesigned instruction fetch unit, which now has more advanced branch prediction that reduces branch bubbles; a balanced instruction fetch bandwidth for increased efficiency; and a smaller, power-efficient instruction queue.

The performance of the L1 and L2 cache systems has also been increased. One of the biggest improvements is seen in the NEON and floating pipeline, which ARM said now has five times the double-precision floating-point performance of the Cortex-A7, and twice as much single-precision floating-point performance.

In the 32-bit mode, Cortex-A35 is expected to deliver 16 percent higher performance than Cortex-A7 at the same clock speed. Its frequency can also be scaled up to 2 GHz, where ARM said it can deliver 84 percent higher performance.

The Cortex-A35 should also deliver from 6 to 40 percent higher efficiency, compared to Cortex-A7 depending on the workload.

Thanks to the improved memory subsystems, ARM said that the Cortex-A35 gets 3.75x the performance of Cortex-A7 for memory intensive tasks. Cortex-A53 also saw an improvement of 2x in this area, so on paper the Cortex-A35 almost doubles the memory subsystems' performance again.

The new CPU gets a low-power mode as well, even though it's quite low-power to begin with. As we've seen with the recent Doze feature in Android 6.0, the main players in the Android ecosystem seem to be focusing on reducing standby power as a way to increase overall battery life of a device.

Besides being its most efficient processor, the new Cortex-A35 is ARM's most configurable 64-bit core, too, according to the company. It's also fully backwards compatible with Cortex-A7, which should make it easy for chip makers and OEMs to support it in their systems.

The Cortex-A35 is expected to arrive by the end of next year in devices, or roughly two years after Cortex-A53 first started shipping.

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Lucian Armasu joined Tom’s Hardware in early 2014. He writes news stories on mobile, chipsets, security, privacy, and anything else that might be of interest to him from the technology world. Outside of Tom’s Hardware, he dreams of becoming an entrepreneur.

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