Radeon Vulkan Driver Adds Option Of Rendering Less For ~30% Greater Performance
If your current Vulkan-based Radeon Linux gaming performance isn't cutting it and a new GPU is out of your budget or you have been unable to find a desired GPU upgrade in stock, the Mesa RADV driver has added an option likely of interest to you... Well, at least moving forward with this feature being limited to RDNA2 GPUs for now.
RADV as Mesa's Radeon Vulkan driver has added an option to allow Variable Rate Shading (VRS) via an environment variable override. This RADV addition is inspired by the likes of NVIDIA DLSS for trading rendering quality for better performance but in its current form is a "baby step" before being comparable to DLSS quality and functionality.
With Mesa 21.1 Git by setting the environment variable such as RADV_FORCE_VRS=2x2, variable rate shading will be enabled to reduce the number of fragment shader invocations per pixel rendered to one per 2x2 pixels. This Vulkan variable rate shading with RADV is currently only supported for Radeon RX 6000 series (RDNA2) GPUs.
This can improve the RADV performance by upwards of 30% but gamers will likely notice the lower quality visuals.
RADV co-founder Bas Nieuwenhuizen of Google has written more about the early RAV VRS support via this blog post for those interested in all the details. Look for this functionality with this quarter's Mesa 21.1 release.