Unexpected Access: How an AMD Leak Brings FSR4 to Older GPUs
In a surprising turn of events, AMD’s accidental release of FSR4 source code has enabled modders to bring the next-generation upscaling technology to graphics cards that AMD never officially intended to support. When the company briefly published—then quickly removed—the FSR4 code repository, it included an INT8 (8-bit integer) version that community members have now compiled into working DLL files, allowing Radeon RX 7000 series and NVIDIA GeForce RTX 30 series owners to experience FSR4’s improvements ahead of schedule.
The leak occurred when AMD mistakenly published the FSR4 source code under an MIT license, leaving it accessible for several days before removal. While the initial release contained only uncompiled weights that were useless to most users, the Reddit community quickly assembled the necessary components into functional DLL files that can be simply dropped into game directories to enable FSR4 support.
Performance and Quality Trade-Offs
Early testing reveals both significant benefits and notable drawbacks to the modded FSR4 implementation:
- Image Quality: Described as “substantially superior” to FSR 3.1 with better detail preservation and reduced artifacts
- Performance Cost: Higher processing time—1.9 ms compared to 0.6 ms for FSR 3.1 on an RTX 3060 Ti
- Compatibility: Works on Radeon RX 7000 series and NVIDIA RTX 30/40 series, but not on RX 6000 cards due to lacking WMMA matrix acceleration
The leaked INT8 version differs from AMD’s official FP8 (8-bit floating point) implementation that requires RDNA 4 architecture. This suggests the INT8 variant may have been an early development version that AMD abandoned in favor of the hardware-specific FP8 approach.
Community Response and Implementation
Enthusiasts have already demonstrated FSR4 working in games like Cyberpunk 2077 through tools like OptiScaler, which simplifies the installation process. Precompiled DLL files are circulating online, allowing technically inclined users to experiment with the technology, though this comes with the standard risks of using unofficial software modifications.
The situation creates an interesting dilemma for AMD: the company never announced plans to bring FSR4 to RDNA 3 graphics cards, focusing instead on making it an exclusive feature for RDNA 4 to drive sales of the new architecture. The leak undermines this strategy by demonstrating that the technology can indeed run on older hardware, albeit with different performance characteristics.
Legal and Ethical Considerations
While the source code was briefly available under an MIT license, AMD’s accidental release creates legal ambiguity about whether the license truly applies. However, the several-day availability window makes enforcement challenging, and the open-source nature of the license typically allows for modification and redistribution.
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- AMD RDNA5 Flagship GPU Rumored – 512-Bit Bus & 96 CUs to Challenge NVIDIA
The Bottom Line
AMD’s accidental FSR4 leak has given the modding community an unexpected opportunity to experience next-generation upscaling on current hardware. While the implementation isn’t perfect—coming with increased performance overhead—it demonstrates tangible image quality improvements over FSR 3.1 and highlights the community’s ability to extend technology beyond manufacturer intentions. For now, curious users can experiment with the leaked version while awaiting AMD’s official FSR4 release later this year.
Source: Sebastian Castellanos, r/radeon