Microsoft previews DirectX 12 update for ray tracing performance
Microsoft released a preview version of DirectX on Wednesday, October 28, that significantly reduces the computational workload required for ray tracing in animated scenes, achieving a leap in performance from 1.2 to 79 frames per second in a developer demonstration. The update targets the demanding process of simulating light paths for realistic reflections and shadows, altering how graphics cards track scene geometry.
The software changes arrive via an Agility SDK preview detailed on the DirectX blog, allowing game studios to adopt advanced DirectX 12 capabilities without waiting for a full Windows operating system update. While the technology does not instantly boost frame rates in existing software, it provides foundational tools for upcoming titles to render far richer visual scenes while controlling performance costs.
Reengineering Scene Blueprints for Animation
To calculate where individual light rays strike objects, graphics hardware traditionally maintains an acceleration structure representing the scene. Rebuilding this blueprint becomes exceptionally costly when animated assets like trees move or environments load continuously.
Cluster Geometry and Partitioned Structures
The preview introduces cluster geometry, which breaks objects down into small packets of up to 256 triangles that game engines can assemble and reuse rather than recalculate entirely. Alongside this, partitioned structures, known as PTLAS, update exclusively the zones within a scene that have experienced physical movement.
Cluster Features Boost Frame Rates and Reduce Memory
Testing these features on an AMD Radeon RX 9070 graphics card using a custom developer demonstration, Microsoft recorded an increase from 1.2 frames per second—calculated when reconstructing every object triangle by triangle—to 79 frames per second with clusters enabled. The time required to construct the scene blueprint dropped from 788 to 3.11 milliseconds, while memory consumption for these structures fell from 7,519 megabytes to 774 megabytes. Temporary memory usage during construction, however, increased from 1.83 megabytes to 526 megabytes for stationary objects.
Hardware Compatibility Across Manufacturers
Microsoft stated that the new functions demand no novel hardware capabilities beyond existing ray tracing support, leaving implementation dependent on manufacturer-supplied drivers. Current driver support spans Nvidia GeForce RTX cards, AMD Radeon RX 9000 models, Intel Arc series B graphics cards, Core Ultra 200V processors, and Core Ultra Series 3 chips. Qualcomm Snapdragon X2 processors are also slated to receive compatible drivers in the first half of 2027.
DirectX Creates Unified Approach Despite Legacy Hardware Limits
Older hardware lines, including AMD Radeon RX 7000 cards, are currently absent from the supported list, and Microsoft cautioned that legacy architectures may lack the necessary performance to ever receive compatibility. While titles like Gears of War: E-Day utilize similar techniques via proprietary interfaces such as Nvidia’s RTX Mega Geometry, the inclusion of these methods in DirectX establishes a unified approach across multiple hardware brands.
Shader Model 6.10, which governs the execution rules for rendering shaders required by cluster geometry, is scheduled to exit preview status in early December alongside the release of Agility SDK 1.621. Microsoft has not announced a formal release date for the final version of the cluster and PTLAS tools.