AMD has officially released its new FSR SDK 2.1.0, the first version to launch under the company’s updated “Redstone” branding. Developers can now download it from GPUOpen and GitHub. The update focuses on DirectX 12 applications running on Windows 10 and Windows 11 and brings major architectural changes, especially in how machine learning is used inside FSR.
New Machine Learning Features
The latest SDK adds four ML-powered features: FSR Upscaling 4.0.3, Frame Generation 4.0, Ray Regeneration 1.0, and a preview version of Radiance Caching.
AMD says FSR Upscaling 4.0.3 isn’t entirely new but an updated version of the upscaler with an improved naming style. The other three features are brand-new and built on neural rendering technology.
Radiance Caching is still in an early stage and only available as sample code and a preview DLL, meaning it will likely be a while before it appears in actual game releases.
New API Structure
FSR SDK 2.1.0 introduces a proper FSR API framework. It now uses a central loader called amd_fidelityfx_loader, along with separate DLLs for the upscaler, frame generation, denoiser, and radiance caching components.
This modular setup allows future AMD Adrenalin drivers to update ML components on their own. In practice, that means games using older FSR versions like FSR 3.1 could eventually benefit from new features—such as FSR Upscaling 4.0.3 or Frame Generation 4.0—without needing a game-specific patch. AMD also released an updated Unreal Engine plugin to support these changes.
Hardware Support and Source Code
The machine learning features will only work on Radeon RX 9000-series GPUs and newer RDNA 4 hardware. Older AMD GPUs and competing hardware will fall back to using the standard analytical FSR 3.1.
AMD provides developers with sample code, but the ML components themselves—FSR Upscaling 4.0.3, Frame Generation 4.0, Ray Regeneration 1.0, and Radiance Caching—are released as pre-compiled, signed binaries. This means they are not fully open source, even though AMD is offering integration guidance and partial code snippets.
With this release, AMD is setting the foundation for how future games will integrate FSR and how advanced ML features will work across different GPU generations.
