ZCULL Support For Nouveau + NVK Brings Some Small Performance Gains

Mesa 26.1 adds ZCULL support to NVK, bringing modest performance improvements to the open-source NVIDIA driver stack.

Written by Michael Larabel in Nouveau on 26 February 2026 at 06:10 AM EST. 2 Comments

Merged yesterday to Mesa 26.1 for the open-source NVIDIA Vulkan driver "NVK" is ZCULL support for more efficient rendering and bringing some small performance gains to this open-source NVIDIA driver stack.

Merged yesterday for next quarter's Mesa 26.1 release is ZCULL support for NVK. While merged, this does depend upon some Nouveau kernel driver patches too that have yet to reach the mainline Linux kernel. The Nouveau driver patches allow using the ZCULL hardware of NVIDIA GPUs for improving the memory bandwidth thanks to an early depth test similar to HiZ on AMD GPUs. This ZCULL hardware support has appeared -- and unchanged -- on NVIDIA GPUs going back at least a decade and a half. The Nouveau driver patches hopefully will be queued up for the Linux v7.1 cycle this summer especially now that the NVK user-space support is ready to go and mainlined in Mesa.

This merge request landed the ZCULL support in NVK. Mel Henning who led the ZCULL effort for NVK commented in the Mesa merge request: "I'm seeing about a 3% improvement in the score in Horizon Zero Dawn's built-in benchmark (7183 -> 7431) on the most recent version of this MR. ... Seems to also bring Baldur's Gate 3 character creator from 31 to 33 fps."

Every bit counts as Nouveau+NVK continues to work toward making NVIDIA gaming atop a fully open-source driver stack more of a reality.

2 Comments