Arm today announced its new flagship Immortalis GPU, the first with hardware-based ray tracing on mobile. As PCs and the latest Xbox Series X and PS5 consoles all gradually evolve into impressive ray-traced visuals, Immortalis-G715 is designed to be the first GPU from the Arm to deliver the same on Android phones and tablets.
Built on top of Mali, a GPU used by MediaTek and Samsung, Immortalis is designed with 10-16 cores in mind and promises a 15 percent boost over the previous generation of premium Mali GPUs. Arm sees Immortalis as the beginning of a move to ray tracing on mobile after its success with the 8 billion Mali GPUs shipped to date.
“The challenge is that Ray Tracing techniques can use significant power, energy and surface area across the mobile system-on-a-chip (SoC),” explains Andy Craigen, director of product management at Arm. “However, Ray Tracing on Immortalis-G715 uses only 4 percent of the shader core area, while delivering over 300 percent performance gains through hardware acceleration.” It’s not clear if a 3x acceleration over software-based ray tracing will be enough to entice game developers, but when Nvidia introduced hardware-accelerated ray tracing in its RTX 2080, it advertised a 2x-3x boost at the time.
Arm is already delivering software-based ray tracing in last year’s Mali-G710, but the promise of hardware support means we’ll see flagship smartphones with this chip in early 2023. Also Samsung announced its Exynos 2200 chip with hardware-based ray tracing earlier this year, so manufacturers are gearing up for the games’ arrival.
“We’ve decided to introduce hardware-based Ray Tracing support now on the Immortalis-G715 because our partners are ready, the hardware is ready, and the developer ecosystem is ready (about to be ready),” said Craigen. Arm offers just a few samples of ray tracing on its mobile GPUs today, and there’s no clear commitment from game developers yet. “We believe this technology has a strong place, but it will take time,” said Arm’s Paul Williamson, pointing out that we should see “some interesting experiences on mobile” in the coming year.
Arm has also updated its main Mali line with the Mali-G715. This GPU includes variable rate shading (VRS) to improve gaming performance and power savings on mobile. VRS essentially renders the parts of a scene in a game that require more detail, so details in the background don’t need as much rendering power. “When enabling Variable Rate Shading on game content, we’ve seen improvements of up to 40 percent at frames per second,” Craigen claims. Other improvements mean these latest Arm GPUs will see a 15 percent power efficiency improvement over the previous Mali-G710 GPU introduced last year. Arm wouldn’t say how much more expensive an Immortalis device could be compared to one in Mali.
Arm’s move to support hardware-based ray tracing on its GPUs is an important step for Android mobile gaming. Ray tracing is currently limited to high-performance GPUs typically found in gaming PCs or the latest Xbox Series X and PS5 consoles. Nvidia has previously demonstrated ray tracing paired with Arm last year, but it was an RTX 3060 GPU paired with a MediaTek Kompanio 1200 Arm processor. That effort is focused on PCs and probably Chromebook-style laptops, but Arm’s new Immortalis is completely focused on Android.
Epic Games supports Immortalis with its Unreal Engine, in addition to MediaTek and Unity. This is the kind of industry support you’d expect for a new mobile GPU like this, but the real test will be how much mobile game developers are going to implement ray tracing. (Arm says his ray tracing will use the Vulkan API.) It’s still incredibly rare to see ray tracing on console games, so it’s unlikely we’ll see a flow of mobile games to ray tracing anytime soon.
Correction, June 28 11:50 AM ET: Article updated with more details on Immortalis, and to clarify, this is Arm’s first hardware-based ray tracing chip, not an industry first.