DirectX Update Promises Major Ray Tracing Memory Reductions

Microsoft is previewing a significant update to DirectX that could dramatically reduce the memory required for ray tracing effects in games. Codenamed 'Clustered Geometry' and 'Partitioned TLAS,' these new features are described by Microsoft as the "most significant update [to DXR] since its debut in 2018." Microsoft's internal testing suggests a potential memory load reduction of up to 90%.

How it Works

Traditional ray tracing can be memory-intensive because it requires detailed geometric models to be processed for each frame. The new DirectX update addresses this by breaking down detailed models into smaller packages of 256 triangles or fewer with Clustered Geometry. Partitioned TLAS then divides the overall scene into smaller regions. Instead of re-evaluating the entire scene for changes, the system only needs to process the specific regions that have been altered, significantly reducing the data the GPU must handle.

Microsoft's testing on an AMD Radeon RX 9070 demonstrated this capability by reducing memory usage from 7.5 GB to 774 MB, while frame rates increased from a low 1.2 fps to 79 fps. This optimization aims to make ray tracing more accessible on existing hardware without the need for costly upgrades.

Caveats and Availability

While promising, Microsoft cautions that not all games will see the same level of improvement. Developers may also face new challenges, as working with clustered geometry and its associated data packages requires more temporary scratch memory. The update is not yet widely available, and there is no release date for consumers. PC gamers interested in testing these experimental features can access them by using compatible Agility SDK preview headers and runtimes, a supporting driver, and Windows Developer Mode.

This development comes at a time when the cost of PC hardware, particularly memory and GPUs, has been on the rise. The potential for significant performance and memory improvements through software updates could offer welcome relief to PC gamers looking to extend the lifespan of their current systems.