NVIDIA GeForce RTX 3090 - Windows vs. Linux GPU Compute Performance
The Blender performance for its CUDA and OptiX code-paths tended to enjoy the best performance out of the GeForce RTX 3090 on Ubuntu Linux.
The proprietary V-RAY renderer with its OptiX/RTX back-end saw similar performance between operating systems while with the older CUDA back-end saw better performance on Ubuntu 21.04 with the NVIDIA proprietary driver.