Low-Power GPU for IoT

The Mali Graphical Processing Units or GPUs from ARM are popular because of their cost efficiency. ARM has optimized them to provide energy efficient, high performance graphics in the smallest possible area of silicon. As a result, not only low- to mid-range smartphones, but also tablets and DTVs are also using Mali cost efficient GPUs as ARM offers a diverse selection of scalable solutions involving both graphics-only and graphics plus GPU Compute technology.

ARM offers the Mali-400MP, which is the first OpenGL, ES 2.0, multi-core GPU with leading area efficiency and the Mali-450MP, which offers approximately twice the performance of the Mali-400MP. However, these are not suitable for the Internet of Things, as these devices require extremely low levels of energy consumption. For the IoT, ARM has released a new low-power GPU. Useful for wearable and other IoT gadgets, the new 32-bit Mali-470MP from ARM claims smartphone-quality graphics, while requiring only half the power used by the Mali-400MP, using the same process geometry.

For cutting the power consumption in the Mali GPUs, ARM targeted three prime areas and made a range of micro-architectural optimizations. They updated most of the processing blocks within the chip to a scheduling pipelines operating on quads. They reduced the frequency of control and state-update operations. They also increased the amount of clock gating in areas including LI caches and completed the bypass blocks.

In general, most graphic processors use floating-point arithmetic for better performance. However, using floating-point arithmetic consumes a lot of power. In Mali-470MP GPUs, ARM prefers using fixed-point arithmetic in places where it does not affect performance. By scrutinizing every milli-watt across the entire SOC, ARM was able to tune the efficiency of Mali-470MP, making it relevant for devices operating with low power budgets, but requiring sophisticated graphics such as wearables, IoT devices and entry-level smartphones.

According to Dan Wilson, Product Manager of ARM, the Mali-470MP is highly power-efficient because it is optimized for the OpenGL ES 2.0 API and its drivers. As most of the devices using Android, Android Wear and Tizen devices use the OpenGL ES API, Mali-470MP can replace the previous generation of GPUs from ARM. Additionally, there is no need to re-optimize the applications for the new GPU.

Just as users are accustomed to vibrant displays and touch interfaces on smartphones, Mali-470MP is expected to bring immersive experiences to wearables, because of its greater power efficiency and support for the OpenGL ES 2.0.

Designers have the freedom of using the multi-core configurable Mali-470MP with both 32- and 64-bit CPUs. These include processors such as the ARM Cortex-A7 and the Cortex-AS3. As IoT devices do not need to address more than 4GB or memory, ARM has designed the new CPU as a 32-bit device. However, Mali-470MP offers optimal energy efficiency when used for screen resolutions up to 640x640p in single-core configurations and up to 1080p for multi-core configurations.

However, the new GPU from ARM is not available in the market yet, and licensees will most likely be able to ship products based on the new Mali-470MP only by the end of 2016.