ARM Holdings is the British company responsible for designing one of the fundamental parts of our smartphones and tablets, the processor core, which is at the heart of the device and controls every other aspect. ARM Holdings design the architecture, leaving other companies to design the System-on-Chips (or SoCs) such as Qualcom, Nvidia, MediaTek, by adding the GPU (graphics processor unit), radios, power management and many other subcomponents. The current high end flagship SoCs for the most part use 64-bit ARM Cortex-A53 processor cores combined with Cortex-A57 cores, representing the LITTLE and big parts of the big.LITTLE modern processor. A big.LITTLE processor combines lower powered, high efficiency processor cores (the A53) with more powerful, but less efficient cores (the A57). We've already seen ARM introduce the Cortex-A72 core, which is just starting to see service in designs around the world and today, we write of a rumored leak detailing no less than five new ARM processor core designs: Ares, Prometheus, Artemis, Ananke and Mercury. These processor cores appear designed for die sizes of both 10nm and 16nm, straddling the current 14nm fabrication process used for the Samsung Exynos 7420.
Let me share a few words about the importance of the die size of a given processor. This is because the smaller the die size, the less voltage is required to drive the processor core and because of this the lower the power needed. Power consumption is proportional to the square of the voltage used to drive the processor, meaning that a relatively small reduction in voltage can give rise to significant power savings within the design. Most recent Qualcomm processors used in devices are typically built on a 28nm fabrication process, dropping to 22nm for some Intel Core processors. Apple and Samsung have dropped to a 20nm and 14nm fabrication process.
ARM have often fielded a family of processor cores, each with a different point along the power and performance scale. The Ares core is the high end processor, which will ultimately replace the Cortex-A72 and is designed with a power envelope of 1 to 1.2W per core. Ares is considered a processor design suitable for enterprise or server clamshell devices, or large targets, as it is too greedy (and perhaps too hot) for smartphones. Instead, smartphones will receive the Prometheus core, likely to be built around the 10nm die size and a replacement for the Cortex-A57 with a power consumption envelope of 600 to 750mW per core.
ARM anticipates that the new Artemis core, to be built on a 16nm process, will replace part of the Cortex-A57 (and 32-bit Cortex-A17) market. The Ananka core is designed as a highly efficient core (with a target power consumption of 100mW to 250mW per core) to replace the remainder of 32-bit A17 market and part of the 64-bit Cortex-A53 market; these processor cores are destined for the lower to mid-range smartphone markets and will support big.LITTLE architecture. The final processor core, Mercury, is to be built with a power envelope of 50 to 150mW per core in mind and is designed for the entry level smartphone and wearable market.
At this juncture, we don't have an estimation for when the new family of ARM cores will be available for the market but it seems a reasonable bet that we are looking at early 2016 at the soonest. The leak is not completely comprehensive when it comes to die sizes for all of the core designs, either because this information is not known or because the cores may be built at different sizes. From the range above, we can see quite the overlap between the different processor core types, which is very much as expected as these processors will likely have a reasonably linear seat of features and this overlap will better allow the manufacturers to pick and choose the best product for the target device.