Compatibility Report
- Name of the game with compatibility issues: EzBench
- Steam AppID of the game: 770170
System Information
I confirm:
Symptoms
The DirectX 12 renderer exhibits significantly lower performance under Proton than both Windows and the DirectX 11 renderer.
Using the default renderer (VKD3D):
When forcing DirectX 11 (-dx11 launch option):
- Performance increases to approximately 120 FPS.
- Benchmark score increases to approximately 14,000.
On Windows, the benchmark scores approximately 11,000 on the same hardware.
The issue therefore appears to be isolated to the DirectX 12 / VKD3D rendering path rather than Proton or the graphics stack in general.
System uses:
- AMD Radeon RX 9070 XT
- RADV
- Mesa 26.1.6
- Linux 7.1.5
- Wayland session on COSMIC / KDE
Reproduction
- Install EzBench (AppID 770170).
- Run the game with Proton Experimental using the default launch options.
- Start the benchmark.
- Observe that the frame rate begins around 60 FPS but quickly falls to approximately 20–30 FPS while GPU utilization remains at ~100%.
- Exit the game.
- Add
-dx11 to the game's launch options.
- Run the benchmark again.
- Observe that performance increases to approximately 120 FPS and the benchmark score rises from roughly 11,000 to 14,000.
Additional observations
- Vulkan is provided by RADV.
- Hardware acceleration is working correctly.
glxinfo and vulkaninfo both correctly detect the AMD Radeon RX 9070 XT.
- No evidence of CPU bottleneck or software rendering.
- The issue appears specific to the DirectX 12 (VKD3D) rendering path.
Compatibility Report
System Information
I confirm:
Symptoms
The DirectX 12 renderer exhibits significantly lower performance under Proton than both Windows and the DirectX 11 renderer.
Using the default renderer (VKD3D):
Benchmark starts at approximately 60 FPS and quickly drops to 20–30 FPS.
MangoHud reports:
When forcing DirectX 11 (
-dx11launch option):On Windows, the benchmark scores approximately 11,000 on the same hardware.
The issue therefore appears to be isolated to the DirectX 12 / VKD3D rendering path rather than Proton or the graphics stack in general.
System uses:
Reproduction
-dx11to the game's launch options.Additional observations
glxinfoandvulkaninfoboth correctly detect the AMD Radeon RX 9070 XT.