Arm Jumps On Ray Tracing Bandwagon With Beefy GPU Design

Arm is beefing up its role in the rapidly-evolving (yet long-standing) hardware-based real-time ray tracing arena.

The company revealed on Tuesday that it will introduce the feature in its new flagship Immortalis-G715 GPU design for smartphones, promising to deliver graphics in mobile games that realistically recreate the way light interacts with objects.

Arm is promoting the Immortalis-G715 as its best mobile GPU design yet, claiming that it will provide 15 percent faster performance and 15 percent better energy efficiency compared to the currently available Mali-G710.

The company managed to generate some excitement about its ray tracing capabilities from two hardware partners: Taiwanese chip designer MediaTek and Chinese phone maker Oppo, with the latter stating "the implementation of ray tracing is certainly an exciting prospect for the mobile gaming industry."

The reveal comes after South Korea-based Samsung announced in January that it will bring hardware-based real-time ray tracing to smartphones with AMD's RDNA 2 GPU architecture integrated in its new Arm-based Exynos 2220 processor.

Months before that, fellow British chip designer Imagination Technologies announced a new mobile GPU design that will come with similar hardware-based ray tracing.

Arm revealed the Immortalis-G715 alongside two other GPU designs that won't support this kind of ray tracing, the Mali-G715 and the Mali-G615, which are made for devices with lower power and performance requirements.

While the Immortalis-G715 can pack more than 10 GPU cores, the Mali-G715 can only hold seven to nine cores. The Mali-G615 maxes out at six cores.

All three GPU designs come with a new execution engine, which serves as the foundation for graphics processing, and a new feature called variable rate shading, which Arm said will enable up to a 40 percent boost in gaming performance while also saving energy for better battery life.

What makes hardware-based ray tracing possible in the Immortalis-G715 is Arm's new Ray Tracing Unit, which takes up less than 4 percent off the area of the GPU's shader core, yet provides a 300 percent boost in ray tracing performance, the company claims.

Another area where Arm was able to squeeze out more performance is the redesigned execution engine, which they say will double the compute power while only using 25 percent extra die space compared to the previous flagship Mali-G710 GPU.

The chipmaker is also touting a new variable rate shading feature, which decouples the GPU's rasterization frequency from the shading frequency to reduce the amount of shading work needed to provide an image that still looks appealing to the human eye. This reduction in the shading rate translates into both an increase in performance and a reduction in energy consumption, according to Arm.

Arm knows it needs the support of developers to make its GPU designs attractive to licensees, so the company made sure to highlight collaborations with the Unreal and Unity game engines, a library of developer resources, and the Arm Mobile Studio suite of profiling tools.

While Arm says all the new GPU improvements are worthy of attention, it emphasizes that the hardware-based ray tracing in the Immortalis-G715 will represent a "paradigm shift" for mobile gaming.

"The ecosystem is ready for it. Our partners want it. The OEMs want it. And this is the start of a journey of implementing ray tracing in mobile that will grow over time," Arm's Craigen said. ®