Open-Source RADV Driver Begins Working To Improve AMD RDNA4 Ray-Tracing Performance

Written by Michael Larabel in Radeon on 17 April 2025 at 08:30 PM EDT. 42 Comments

While the Radeon RX 9070 series as the first of the AMD RDNA4 graphics cards do perform well on Linux, the one area the performance has been less enticing remains with Vulkan ray-tracing while using the Mesa RADV driver. For example, AMDVLK vs. RADV on the RX 9070 series shows the Mesa driver struggling with ray-tracing compared to the official AMD driver. But the good news is there's a concerted effort now to improve the AMD RDNA4 ray-tracing performance with RADV.

Konstantin Seurer who is a contractor for Valve and working on the Mesa RADV driver has begun focusing on the RDNA4 (GFX12) ray-tracing performance and the work needed to get that performance in better shape.

Merged today was the first step in that journey with switching to the BVH8 format on the AMD GFX12 (RDNA4) hardware. The German open-source developer explained in that merge request:

"This is the first big step towards good ray tracing performance on GFX12 since it adds support for the new bvh format. I don't expect this MR to improve performance by much (if at all) on its own. It does not use some hardware capabilities and is sub-optimal in a lot of places. I decided to land the initial support before looking into performance improvements because it is quite a lot of code with countless possibilities for introducing regressions."

So this is just the first step in the direction of better AMD RDNA4 Vulkan ray-tracing performance.

👁 Radeon RX 9070 graphics card

At least with one of the Valve developers working on it, this improved ray-tracing performance for these newest AMD discrete GPUs will hopefully materialize sooner than later.

This work is coming too late for Mesa 25.1 that was branched yesterday but hopefully all of this RDNA4 ray-tracing work will be settled by the time Mesa 25.2 is out as stable in August.