When NVIDIA released TXAA, they were trying to reduce temporal aliasing which produces crawling and flickering in motion during gameplay. TXAA is a mix of the already known Multi-Sample AA (MSAA) along with a custom CG film style Anti-Aliasing and a temporal filter. To correct the sharpness of each pixel structure, TXAA gathers samples from inside and outside the pixel as well as samples from other frames to filter each pixel. This greatly improves the spatial filtering over the standard MSAA filtering and can be clearly seen on objects such as fences and foliage.
Another improvement over FXAA, is TXAA’s capability to intelligently manage per-pixel effects (such as atmospheric rendering) without introducing weird lighting artifacts on structure edges. What is interesting, is that in motion scenes, TXAA can be compared to other high end professional AA algorithms that are usually not available for end users today, but rather on the enterprise hardware from which TXAA was developed from.
As you may notice the differences per frame between TXAA, FXAA, and 4x MSAA are almost minimal, however TXAA brings the added benefit of reducing temporal aliasing when in motion throughout the game. The performance impact of TXAA is also different as it varies depending on the type of shading between each game. During our Assassins Creed Unity test we noticed that the performance was relatively similar to that of FXAA.