A partially redacted data sheet highlighting the expected ray tracing features coming to RDNA 4 GPUs has been shared by well-known hardware information leaker @Kepler_L2. We expect the features to also be present in the hybrid RDNA 3 + RDNA 4 RT design coming to PS5 Pro when it launches (presumably) later this year or early next year. The leaked data points seem to confirm that advancing ray tracing technology is going to be a major focus of RDNA 4.
Some of the new RT features coming with gfx12/RDNA4. Most if not all of these should be in the PS5 Pro too 🙂 pic.twitter.com/AO5HaxJlMKJuly 21, 2024
Leaked RDNA 4 Ray Tracing Features
- Double Ray Tracing Intersect Engine
- RT instance node transform
- 64B (byte) RT node
- Ray Tracing Tri Pair optimization
- Change flags encoded in barycentrics to simplify detection of procedural nodes
- BVH Footprint Improvement
- RT support for OBB and Instance Node Intersection
Previously, leaks have pointed toward RDNA 4 delivering a massive overhaul of AMD's existing RT hardware in the interest of turning around a more performant, more competitive solution to Nvidia's market-leading RT technology. The peak of RDNA 3 GPU architecture, the Radeon RX 7900 XTX, still crumbles compared to the yet-older RTX 3090 Ti when put in ray tracing workloads — yet rasterized performance still exceeds Nvidia's powerful RTX 4080. Any gains to RT performance for AMD are sorely needed.
Of the listed improvements, the ones that seem most promising are "Double Ray Tracing Intersect Engine", "64B RT node", and "Ray Tracing Tri Pair Optimization". These all seem to point toward significant improvements in both ray tracing precision and ray tracing performance.
Other listed improvements also seem characteristic of precision and efficiency improvements in general, which may mean AMD is hoping to match the yet greater RT fidelity offered by ray reconstruction. Although the AI hardware in RDNA 3 has thus far been solely dedicated to AI workloads rather than RT or even FSR image scaling, sadly.
Until we see some real RT benchmarks on RDNA 4 hardware, we really can't glean much meaningful information from these points. While the PS5 Pro is expected to partially utilize RDNA 4 for boosted RT performance, it'll still mainly be built around the RDNA 3 graphics architecture. Meanwhile, mainstream RDNA 4 GPUs aren't even expected to be revealed until the CES of next year, as per another leak from @Kepler_L2 given earlier this month.
