Imagination DXT GPU Adds ALUs, TPUs

Imagination Technologies’ DXT GPU increases raw performance by 50% over the prior CXT generation. Although ray tracing remained in the headlines, changes to other circuits are responsible for this higher throughput.

Bryon Moyer

Imagination Technologies’ DXT mobile-GPU family improves the architecture and implementation to raise performance and performance density relative to the older CXT-series. Although ray tracing remains the top-line feature, it’s unchanged from the prior generation.

The company made selective enhancements in areas that were bottlenecks, including the texturing engine, texture compression, how scenes are prepared for rendering, and the top-level CPU that Imagination calls the “firmware processor.” Architecturally, the number of ALUs and texture units (TPUs) grew by 50% compared with the prior generation.

Imagination was first to accelerate smartphone-compatible ray tracing with its CXT family in late 2021. Last year, MediaTek, Qualcomm, and Samsung implemented the capability in their premium-smartphone chipsets, with MediaTek and Samsung relying on licensed technology.

Ray tracing has appeared only in the most expensive phones, limiting the installed base, and game makers want a sizable opportunity before employing a new technology. The feature will likely be mainstream in about two years—the period between intellectual-property (IP) licensing and the launch of phones that contain it. Consequently, Imagination has focused on reducing power and cost to enable participation in the mainstream business.

Available for licensing now, the DXT GPUs keep the existing ray-tracing hardware while making improvements elsewhere to enhance their palatability for mainstream phones. Raw performance increases by 50% compared with the CXT, and performance per square millimeter of silicon grows by up to 20%.