Arm’s next-gen Immortalis is more powerful and power-efficient

On Wednesday, IP core designer Arm announced its next-generation CPU and GPU designs for flagship smartphones: the Cortex-X925 CPU and Immortalis G925 GPU. Both are direct successors to the Cortex-X4 and Immortalis G720 that currently power MediaTek’s Dimensity 9300 chip inside flagship smartphones like the Vivo X100 and X100 Pro and Oppo Find X7.

Arm changed the naming convention for its Cortex-X CPU design to highlight what it says is a much faster CPU design. It claims the X925’s single-core performance is 36 percent faster than the X4 (when measured in Geekbench). Arm says it increased the AI workload performance by 41 percent, time to token, with up to 3MB of private L2 cache.

The Cortex-X925 brings a new generation of Cortex-A microarchitectures (“little” cores) with it, too: the Cortex-A725, which Arm says has 35 percent better performance efficiency than last-gen’s A720 and a 15 percent more power-efficient Cortex-A520.

Arm’s new Immortalis G925 GPU is its “most performant and efficient GPU” to date, it says. It’s 37 percent faster on graphics applications compared to the last-gen G720, with improved ray-tracing performance with intricate objects by 52 percent and improved AI and ML workloads by 34 percent — all while using 30 percent less power.

For the first time, Arm will offer “optimized layouts” of its new CPU and GPU designs that it says will be easier for device makers to “drop” or implement into their own system on chip (SoC) layouts. Arm says this new physical implementation solution will help other companies get their devices to market faster, which, if true, means we could see more devices with Arm Cortex-X925 and / or Immortalis G925 than the few that shipped with its last-gen ones.

As a bonus for mobile game developers, Lumen ray tracing on Unreal Engine now supports Immortalis. It’s unclear if that alone will be a big enough incentive for more game developers to add ray tracing to their mobile games or how those games would perform. As Andy Craigen, director of product management at Arm, explained when the company launched its first hardware-based ray-tracing Immortalis design in 2022: “The challenge is that ray tracing techniques can use significant power, energy, and area across the mobile system-on-a-chip (SoC).”

We asked Arm what other mobile devices use its ray-tracing Immortalis GPUs and when we can expect to see a new phone using the Immortalis G925. Currently, the iQOO Neo 9pro is using the Dimensity 9300, while the Xiaomi 14 series and OnePlus 12 series use the Cortex-X4 and Cortex-A720 in a Snapdragon 8 Gen 3. Arm said it expects new phones with its new core designs to become available in late 2024, but could not say from which companies.

However, JC Hsu, Corporate Senior Vice President at MediaTek was quoted in Arm’s press release as saying: “MediaTek is committed to supporting the latest Armv9 Cortex-X925 CPU and Immortalis-G925 GPU Client solution in our next generation flagship chipset, Dimensity 9400, later this year.” So, that could mean we’ll see a new Vivo or Oppo by the end of 2024.

Not too many phones currently use Arm’s Cortex and Immortalis designs together. Other than the current-gen phones already named above, MediaTek’s Dimensity 9200 chip that powered the Vivo X90, X90 Pro, and Oppo Find X6 was the first to use Arm’s flagship hardware-based ray-tracing GPU design, the Immortalis G715, with the Cortex-X4. But it’s more common to find the Cortex paired with another GPU design in a mobile chip like Samsung’s Exynos 2400, which you’ll find in Samsung’s Galaxy S24 and S24 Plus.