Free AMD FSR 4.1.1 Mod Adds AI-Trained “Lossy2” Mode With Up to 25% Higher FPS
A new community-made modification for AMD FidelityFX Super Resolution 4.1.1 is attracting attention for delivering a noticeable frame-rate boost without requiring new hardware. The latest release introduces an AI-trained rendering mode called “lossy2,” which is designed to keep much of the performance advantage of an earlier experimental version while improving image quality in motion.
The mod changes the way AMD FSR processes frames. In the standard implementation, FSR’s neural network runs on every frame. With the lossy approach, that workload is reduced by running the network on alternating frames, while reusing and adjusting previous results for the frames in between. This can significantly improve performance, although it may also introduce visual artifacts depending on the game and scene.
Developer testing shows a strong uplift in Shadow of the Tomb Raider. Using a Radeon RX 7800 XT on Linux at 4K resolution with the Balanced preset, the original AMD shaders reportedly reached 97 FPS. The new FSR 4.1.1 lossy2 version increased performance to 121 FPS, which works out to roughly a 25% gain.
The earlier lossy version already delivered similar speed improvements, so the biggest focus of lossy2 is not simply higher FPS. Instead, the new release aims to improve visual stability and reduce some of the image-quality issues seen in the previous build.
To achieve this, the developer retrained weights in six of the twelve neural-network layers used by FSR. The updated model is said to produce cleaner results in specific problem areas, including moving foliage, thin wires during slow camera movement, and bright visual artifacts. Fine detail preservation also appears to be improved compared with the first lossy implementation.
That said, the performance boost is not free of compromises. The developer notes that lossy2 may react more slowly when brightness increases in a scene. Some static images may also look less accurate, and games with heavy film grain could show weaker results. Ultra Performance mode is not fully supported by lossy2 either; in that mode, the mod falls back to the earlier lossy method.
The modification is available in separate builds for Radeon RX 6000 and Radeon RX 7000 graphics cards, with another version intended for integrated graphics. However, it remains an experimental community project rather than an official AMD release.
Users should also be cautious about where they use it. The developer advises against enabling the mod in online multiplayer games or any title that uses anti-cheat software, as modified rendering files could potentially cause compatibility or detection issues.
While the reported 25% FPS improvement is promising, it comes from the developer’s own benchmark and has not been independently confirmed. Real-world results may vary depending on the GPU, game engine, resolution, graphics preset, operating system, and how each title handles FSR.
For players comfortable with experimental tweaks, the AMD FSR 4.1.1 lossy2 mod could be an interesting way to squeeze more performance out of Radeon hardware. It may be especially appealing for gamers targeting higher frame rates at 1440p or 4K, provided they are willing to accept some visual trade-offs.
