Use the Disable Alpha Test override mode to understand the performance impact of testing each pixel’s alpha component. Performance may increase because at least the same number of pixels will be rendered, but may decrease because alpha blending may be enabled to blend pixels that were rejected by the alpha test.
The Disable Alpha Test override mode might cause rendering artifacts to appear, especially if the scene uses textures or other techniques that would not be rendered due to failing the alpha test
This override is available only for Microsoft DirectX* 9. For Microsoft DirectX* 10 and Microsoft DirectX* 11 applications you should use the Simple Pixel Shader feature to get similar results.