There has been a peculiar gap in ARM’s mobile chip offerings ever since the Cortex-A15 was announced. With A7 on the low-end and A15 on the extreme high-end, ARM was lacking a middle-of-the-road solution for all those budget smartphones.
As we reported earlier today, ARM - at Computex 2013 in Taipei - has announced the architecture to fill in the gaps: The Cortex-A12 processor core, together with the Mali-T622 GPU. These new cores should give ARM system-on-a-chip (SoC) makers, such as Samsung and Nvidia, a powerful and efficient solution for mid-range devices.
This new architecture can’t come soon enough for ARM. The older Cortex-A9 can’t keep up with newer architectures based on x86 and Qualcomm’s custom Krait, but Cortex-A15 needs a lot of power and a large chip to really show what it can do. In a mid-range device, that’s simply not feasible.
ARM is targeting A12 at devices that cost between £150 and £250 unsubsidised. We’re basically talking about those cheap or free on-contract phones that currently struggle to crunch all the necessary bytes.
ARM claims that Cortex-A12 is every bit as efficient as A9, but offers considerable performance gains. Any SoC based on A12 is expected to see 40 per cent gains in single-threaded processing performance over the A9 at the same clock speed. Impressive, but even more so when you consider A12 will have a 30 per cent smaller chip size thanks to its 28nm process technology. Cortex-A9 is still based on the old and clunky 45 and 32nm processes.
Like ARM’s more powerful application processor designs, the Cortex-A12 has support for the big.LITTLE chip design. This SoC configuration pairs several high-power cores with matching low-power Cortex-A7 cores.
This allows a device to only spin up the beefier hardware when the lightweight A7 can’t handle things. Samsung uses this configuration in its Exynos 5 Octa, which has four A15 cores and four A7 cores.
The big.LITTLE design has proven useful with A15 largely because of the inflated power requirements. That’s really the problem A12 is trying to solve for mid-range devices, so it might not be worth the time it takes to develop a big.LITTLE solution for A12 – the A12 may manage just fine on its own.
The Mali T-622 is being billed as the perfect GPU to pair with the Cortex-A7 as it also fits nicely in the mid-range. The T605 is getting long in the tooth, and the T624 is more power hungry and simply overkill for some devices. T622 is a two-core implementation of the updated T600 architecture, known as Midgard. This same tech will be used in the upcoming (and very high-end) T628.
T622 should offer a 50 per cent power efficiency improvement over the older T600 series designs. It supports all the necessary standards with multi-core rendering of OpenGL ES 3.0, DirectX 11, and OpenCL 1.1. Mali-T622 will be made in both single and dual-core versions with a CoreLink cache interconnect linking it to the Cortex-A12 (pictured above). The application processor and GPU can actually share L2 cache in this configuration, allowing for dynamic voltage control and better power management.
The Cortex-A12 and Mali-T622 could soon be licensed by the likes of Samsung to power a new generation of mid-range phones that run longer while annoying the user much less with random slowdowns. ARM expects the first phones and tablets running Cortex-A12 and Mali-T622 to be available around the middle of 2014.