AMD RDNA2 Vulkan: RADV vs. RADV+NGGC vs. AMDVLK vs. PRO Driver Benchmarks

Following last week's Radeon RX 6600 XT launch, here are benchmarks of the Radeon RX 6600 XT / RX 6700 XT / RX 6800 XT graphics cards across all of the Vulkan driver options available to Linux users.

There was the recent RADV vs. PRO Vulkan driver benchmarks, but that's not all of the options, so here is a more comprehensive look at the performance of the different AMD Radeon Vulkan driver options currently available:

RADV - The latest Radeon Vulkan driver option as found within Mesa. RADV is the driver most commonly used by Linux gamers and found out-of-the-box on the various Linux distributions. RADV is what's backed by Red Hat, Valve, and others but not officially maintained by AMD developers. Mesa 21.3-devel Git from the Oibaf PPA was used for testing.

RADV+NGGC - A secondary run of RADV was also carried out when enabling the Next-Gen Geometric Culling (NGGC). NGG Culling was recently added to RADV and previous benchmarks have shown it to help RDNA2 GPUs. It's likely later in the Mesa 21.3 cycle that this NGG culling will be enabled by default but for now on Mesa Git it requires setting the RADV_PERFTEST=nggc environment variable to enable.

AMDVLK - The latest open-source AMDVLK driver. AMDVLK is AMD's official open-source Vulkan driver for Linux systems. AMDVLK is derived from the same sources as their Windows/Linux proprietary driver but built against the open-source AMDGPU LLVM shader compiler rather than AMD's proprietary shader compiler. AMDVLK 2021.Q3.4 was used for testing as their latest public snapshot. As of this latest release there isn't yet RX 6600 XT support but the driver was working fine for the RX 6700 XT and RX 6800 XT.

"PRO" - The closed-source AMD Radeon Vulkan driver shipped with the Radeon Software for Linux driver package when installing the "PRO" driver components. This is similar sources to AMDVLK but using their proprietary compiler. AMDVLK and PRO represent AMD's official Vulkan drivers for Linux systems.

All of the testing was done on the same Ryzen 9 5900X system. Aside from when using the PRO driver components with its DKMS modules, the rest of the time the Linux 5.14 Git upstream kernel was used for the latest AMDGPU DRM driver support otherwise. Radeon Software for Linux 21.30 provided the PRO driver, AMDVLK 2021.Q3.4 was the AMDVLK build, and Mesa 21.3-devel for the RADV tests.

These Vulkan drivers were tested on the RX 6600 XT, RX 6700 XT, and RX 6800 XT. (As mentioned before, no RX 6900 XT Linux tests at Phoronix for never having received the card for testing.) Various Vulkan gaming benchmarks -- both native and via Steam Play -- were carried out across these four prominent AMD Vulkan Linux driver options.