Ray Tracing Takes Pole Position in Mobile GPU Race

As smartphones have become increasingly powerful, the concept of mobile gaming has gathered steam. Premium gaming experiences are supported by a level of performance that was unimaginable even a few years ago, and leaders in chipset design continue to search for the next big gaming performance feature in a fiercely competitive market.

The new frontier for this battle may have arrived in the form of ray tracing. This is a 3D graphical technique that models light transport or rays, using a host of rendering algorithms to generate lifelike scenes of lights and shadows. The resulting render mimics real-world physics to illuminate every object in gameplay. It’s incredibly intensive; each frame of gameplay needs ray-traced rendering as scenes constantly change with shifting perspectives and game movements. Hence, the applications of this high-end digital effect have remained limited to premium gaming consoles and high-end PC gaming rigs.

That is, until now. This week saw Arm announce the Immortalis-G715 GPU, a new design that’ll bring hardware ray-tracing capabilities front and centre for competitive mobile GPUs. Previously, the power consumption requirements of silicon-based ray tracing had precluded use in mobile devices; but the tremendous growth and market demand for sophistication in mobile gaming has prompted the industry to look at applying this technology in a lower-power format, bringing more photorealistic graphical rendering to the masses.

With the announcement of the Immortalis-G715, Arm’s introducing a multi-core GPU design featuring a ray-tracing unit (or RTU) in each of the eight to 16 available cores. This dedicated silicon real estate is the first of its kind for Arm — the latest design also boasts 15% greater energy efficiency over its previous GPUs. Immortalis is naturally geared toward flagship smartphone system-on-chip (SoC) designs; currently, MediaTek is Arm’s main partner for mobile GPU designs. In turn, these compete directly with Qualcomm for the bulk of the mobile SoC market in the larger Android-based hardware network.

Arm is essentially throwing down the gauntlet to market leader Qualcomm to respond with its next GPU upgrade later in 2022. The US firm uses its own GPU design with its multi-generational Adreno GPUs; these have a long history that began with the acquisition of ATI Technologies in 2009. Since then, Qualcomm has developed seven generations of the Adreno GPU — which by many benchmarks leads in performance on the Android hardware market. Qualcomm’s latest Adreno 730 is featured in its Snapdragon 8 and 8+ Gen 1 SoC, featuring leading mobile gaming technologies like variable rate shading. But pressure is now piled on the firm to respond to the ray-tracing challenge and keep pace in the gaming arena.

Samsung is another player in the mobile GPU industry that has touched on ray tracing. It announced its Exynos 2200 SoC earlier in 2022, featuring its new Xclipse GPU powered by AMD’s RDNA 2 architecture. The Xclipse GPU features hardware-based ray tracing as well as variable rate shading. However, given Samsung’s Exynos market share and reach, the technology is likely to be limited to a handful of international versions of its flagship Galaxy devices, starting in 2023.

Apple remains the non-Android player of significance in the mobile GPU space, thanks to its A-series SoC. It began using its own GPU design from 2017, starting with the A11 Bionic line after licensing Imagination Technologies GPU designs for all previous A-series processors. With Apple largely in control of its hardware and software, the need and motivation for the company to move to a hardware-based ray-tracing GPU design is less clear. With the expected update of the iPhone line and arrival of an A16 Bionic processor in September 2022, it’s possible — but improbable — that Apple would add hardware-accelerated ray-tracing circuits in its new GPU design.

For Imagination Technologies, the company announced its IMG CXT mobile GPU design in late 2021; it supports ray tracing, but no mobile chipset manufacturer has announced plans to use this as yet.

The focus on ray tracing in competitive mobile GPU design highlights the growing importance of gaming in mobile applications. User expectations are forcing the market to close the gap between the gaming experience on consoles and smartphones, with chip designers pushing the boundaries of performance. Arm’s announcement of the Immortalis-G715 represents a milestone in mobile GPU design, and ray tracing opens up new opportunities for customers like MediaTek to create a leading hand-held gaming experience — one that could in turn help the firm close its perceived gap in flagship chipsets with Qualcomm.

By winning the race to offer mobile hardware-based ray tracing, Arm will force other significant players like Qualcomm and Apple to take notice of this design trend and respond competitively.