Attack of the 64-bit Octa-core: A Roundup of Newly Announced Mobile Processors


As usual, Mobile World Congress was packed with cool new SoCs, most of which are destined for Android phones and tablets. Some will see wider usage in the broader world of embedded Linux and Android devices.

Intel processors 734xxThe big news was the invasion of 64-bit ARMv8 and x86 SoCs, including Qualcomm’s Snapdragon 615 and Intel’s Atom Z34xx. The ARM models are built on the ARMv8 Cortex-A53 design. Eventually, we’ll see the -A53 used in Big.Little hybrids along with the similarly 64-bit, server-class Cortex-A57.

Most of the 64-bit SoCs target year-end releases, which is likely the earliest Android will add 64-bit support. With the iPhone’s A7 chip, Apple has beaten Android by at least a year.

Another trend at MWC was the arrival of new octa-core models. The only 64-bit octa-core is the Snapdragon 615, which breaks new ground by orchestrating eight Cortex-A53 cores. Others use Big.Little combos that mix lower power Cortex-A7 cores with cores based on the -A15 or the newly announced -A17.

Amazing capabilities should emerge from a desktop-like, 64-bit data path, as well as up to eight tunable cores. Yet, the initial impact will be muted until Android and Android app developers learn how to fully exploit them. Arguably, new graphics co-processors should have a more immediate impact. SoC comparisons increasingly revolve around their associated GPUs, with newcomers including ARM’s Mali-T760, Imagination’s PowerVR Series 6, Qualcomm’s Adreno 405 and 420, and the 192-core Mobile Kepler GPU in Nvidia’s Tegra K1.

Qualcomm Snapdragon 601 and 615

At MWC, the big chip news was Qualcomm’s partial unveiling of its 64-bit Snapdragon 601 and 615. The quad-core, 1.5GHz Snapdragon 601 will land in the third quarter, with shipping devices in the fourth, while the Snapdragon 615 is expected in Q4 2014, with devices following in early 2015. The 615 has the same Cortex-A53 cores as the 601, but it offers eight of them, making it the first homogeneous, ARM-based octa-core SoC aimed at the mobile market. Applied Micro’s X-Gene combines eight Cortex-A53 cores, but is aimed at the enterprise server and networking markets. Like the 610, the 615 features Qualcomm’s new Adreno 405 GPU. Unlike the Apple A7, the new Snapdragons feature integrated LTE and hardware-based 4K video rendering.

These devices follow Qualcomm’s first 64-bit, ARMv8 SoC, the Snapdragon 410, a 1.2GHz quad-core SoC announced in December, due in the second quarter. In the 32-bit realm, Qualcomm also announced a marginally faster 2.5GHz quad-core Snapdragon 801 update to the 800.

The Snapdragon 615 contradicts Qualcomm’s earlier philosophy on two counts. Previously, Qualcomm execs have claimed that octa-core and 64-bit technologies are overkill for mobile. Although they may have been more right than wrong, marketing trumped consistency.

MediaTek and Marvell take 64-bit mid-range

It’s interesting how quickly cutting-edge CPUs now debut on mid-range devices. MediaTek, for example, announced a quad-core, Cortex-A53 based MT6732 SoC designed for “super-mid” market phones due by year’s end. The 1.5GHz, 64-bit MT6732 lacks some of the extras provided by the Snapdragon 615, but taps ARM’s new 16-core Mali-T760 GPU and offers integrated LTE.

Like MediaTek, Marvell is also aiming a new 64-bit SoC at the mid-range market, most likely in China where it has enjoyed a presence with its PXA 1088. The quad-core, Cortex-A53 based PXA 1928 runs at 1.5GHz, is paired with a Vivante GC5000 GPU, and offers integrated LTE.

In late 2014, we should see more 64-bit SoCs, including Nvidia’s ARMv8 version of the Tegra K1, a dual-core, 2.5GHz processor dubbed “Project Denver.” The SoC features 7-way superscalar technology for processing multiple instructions in a single clock cycle, compared to 3-way on the 32-bit Tegra K1.

This week, Freescale VP Tareq Bustami told TechRadar Pro that the 64-bit ARM version of Freescale’s QorIQ SoC will arrive by year’s end. The new QorIQ will be available in both 8- and 12-core configurations. Like the previously announced Altera Stratix 10 SX, an FPGA enabled Cortex-A53 SoC built with Intel’s 14-nanometer (nm) 3D Tri-Gate process, the SoCs are heading for networking and enterprise customers. There was no word on a 64-bit upgrade to Freescale’s Cortex-A9 based i.MX6, a popular SoC in the embedded world.

Intel’s 22nm Merrifield aims for smartphones

No stranger to 64-bit technology, Intel has announced its first 64-bit mobile SoC with the dual-core, 2.13GHz Atom Z34xx (“Merrifield”). The Z34xx is due to arrive in Android phones this summer along with a PowerVR Series 6 GPU and an Intel XMM 7160 multimode LTE chipset. Intel also announced a quad-core, 2.3GHz “Moorefield” version, due by the year’s end, that promises Android 4.4.2 support and an enhanced, potentially Intel-crafted, GPU.

Intel first targeted smartphones with its Atom Z2460 “Medfield” processors, and had more success with last year’s Atom Z2580 “Clover Trail +”. Still, the Atom is only a blip in the mobile market, due primarily to middling battery life.

Those concerns should be history with the Atom Z34xx, which is built on the more efficient Silvermont architecture, featuring 22nm, Tri-Gate 3D fabrication. Silvermont already fuels the Atom Z3000 (“Bay Trail-T”) tablet SoC and the embedded Atom E3800 (“Bay Trail-I”).

Will the Atom Z34xx, or perhaps the upcoming “Moorefield,” be sufficiently competitive to drive a Google Nexus phone? Rumor has it that Google is prepping an Asus-built Nexus tablet based on the Atom Z3000, so a phone could be next. The remaining challenge for Intel no longer appears to be battery life, but price. Intel may need to take an initial loss to make a mark in mobile.

Cortex-A17: MediaTek MT6595, Rockchip RK3288

ARM is billing its 32-bit Cortex-A17 as the heir to the Cortex-A9. Then again, ARM said the same thing last summer about the slower, but similarly 28nm Cortex-A12. The -A17 can also be seen as a more power efficient replacement to the Cortex-A15, which has suffered from lower than expected power efficiency.

The Cortex-A17 is claimed to offer 60 percent faster performance than the -A9, with improved power and area efficiency. Like the Cortex-A15, the -A17 supports Big.Little octa-core combos with -A7 cores. The Cortex-A12 won’t be able to do this until a 2015 update. Unlike the early -A15 SoCs, the -A17 offers full support for heterogeneous multi-processing (HMP), enabling power and performance optimizations for each Big.Little core.

The newly announced Mediatek MT6595 has four 2.5GHz -A17 cores plus four 1.7GHz -A7 cores. No clock rate was listed for Rockchip’s quad-core Cortex-A17 based RK3288. Both the RK3288 and MT6595 are said to support 4K2K video recording and playback. ARM’s suggested Cortex-A17 pairing is a new quad-core Mali-T720 GPU. The Rockchip RK3288 supports this, as well as the 16-core Mali-T760. MediaTek instead opted for a PowerVR Series 6.

Cortex-A15: Samsung, Allwinner keep ’em coming

While we wait for the Cortex-A17 SoCs to arrive in the coming months, there’s still action with Cortex-A15, including updated octa-core models from Samsung and MediaTek. At MWC, Samsung announced a 28nm Exynos 5422 octa-core that finally offers full HMP controls. It features four faster 2.1GHz Cortex-A15 and four 1.5GHz -A7 cores, and supports 4K UHD resolution. Samsung also announced a six-core Exynos 5 Hexa version with dual 1.7GHz -A15 and four 1.3GHz -A7 cores, similarly coordinated with HMP-ready Big.Little technology.

Finally, Allwinner announced an UltraOcta A80 SoC that combines four -A15 and four -A7 cores. The UltraOcta A80 also packs a 64-core PowerVR 6230 GPU.

Correction: Qualcomm’s 64-bit Snapdragon 615 was not the first ever homogeneous, ARM-based octa-core SoC.