AMD has released its FidelityFX SDK v2.2, clarifying exactly how the company plans to split upscaling features between new and legacy hardware. The update introduces "FSR Redstone," a suite that includes FSR Upscaling 4.1, Frame Generation 4.0, and Ray Regeneration 1.1.
While the "4.1" numbering suggests a minor iteration, the underlying shift is meaningful. This is the first version of FSR built on the same neural network architecture as Sony’s PlayStation Spectral Super Resolution (PSSR 2), developed under the "Project Amethyst" banner. For PC users, the benefits of this machine-learning approach come with a clear hardware boundary: the ML-powered features are locked to the new RDNA 4 (Radeon RX 9000) series.
The Four Pillars of FSR Redstone
AMD is moving away from the simple "FSR 4" moniker in favor of a categorized suite. The SDK documentation outlines four technologies that make up Redstone:
- FSR Upscaling 4.1: An updated inference model designed to reduce shimmering and improve sharpness when objects are in motion.
- FSR Frame Generation 4.0: The latest iteration of AMD's frame interpolation.
- FSR Ray Regeneration 1.1: A competitor to Nvidia’s Ray Reconstruction, aimed at cleaning up ray-traced reflections and lighting.
- Radiance Caching 0.9: A technical preview feature intended to improve global illumination.
The shift to a DLL-based architecture via amd_fidelityfx_loader.dll is the most practical change for users. Historically, updating FSR required game developers to patch their titles. This new structure allows for driver-side updates, meaning users might benefit from improved upscaling quality in older games without waiting for a formal developer patch.
Hardware Requirements and the ML Divide
The most important aspect of this release is the bifurcation of the Radeon user base. AMD has a reputation for keeping FSR open to all hardware, but Redstone draws a line in the sand.
Owners of older hardware, including the RX 7000 and RX 6000 series, aren't entirely left behind, but they won't be using the new ML models. Instead, the SDK includes "analytical fallback modes" labeled as FSR 3.1.5. These provide the traditional non-ML upscaling paths for architectures that lack the specific AI accelerators AMD is targeting with RDNA 4.
The software side also has strict requirements. To use the full suite, you’ll need Windows 11 and a GPU capable of Shader Model 6.7, which relies on the DirectX 12 Agility SDK 1.710.2.
Real-World Performance and Quality Questions
AMD’s internal testing claims the Radeon RX 9070 XT achieves an average 3.5x performance boost at 4K when the full Redstone suite is active. However, early third-party analysis suggests the gap with Nvidia hasn't entirely closed. A report from TechSpot indicates that while FSR 4.1 improves detail reconstruction—particularly in fine textures like foliage—it still appears to trail Nvidia’s DLSS 4.5 in overall image stability.
On the driver side, Adrenalin Edition 26.3.1 provides the necessary hooks for these features and adds support for Crimson Desert and Death Stranding 2: On the Beach. Crimson Desert is the first title confirmed to use Ray Regeneration 1.1.
The update isn't without friction. AMD's own release notes mention that FSR features may appear inactive in Battlefield 6 on RX 9000 cards, and users on older RX 5000 series hardware are seeing driver timeouts in Death Stranding 2. Furthermore, the FSR 4.1 update has reached the Unreal Engine 5 plugin, which has been updated to version 4.1.0.
Hardware Longevity and Software Locks
If you are currently on an RX 7000 series card or older, this SDK release suggests that you are likely at the end of the line for AMD's most advanced upscaling research. While you will still see "FSR 4" branding in some games, the actual technology under the hood will be the analytical 3.1.5 fallback rather than the ML-driven 4.1 model.
For those planning an upgrade to the RX 9000 series:
- Expect a Windows 11 requirement: Many Redstone features, specifically Frame Gen 4.0 and Ray Regen 1.1, require the modern OS.
- Watch for game-specific support: Even with the new DLL loader, the best results for Ray Regeneration 1.1 will likely be limited to newer titles like Crimson Desert.
- Vulkan users should wait: The current SDK release is focused on DirectX 12; Vulkan support is missing from this version of the v2.2 toolkit.
The move toward signed, pre-built binaries for the machine learning components also signals a shift in AMD's "open source" philosophy. While much of the SDK remains accessible, the core neural networks are now closed-box, bringing AMD's development model closer to the proprietary approach used by Nvidia and Sony.
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