Just weeks after the AMD FSR 4 source code was unexpectedly made public, enthusiastic gamers have been rigorously testing it on older RDNA 2 and RDNA 3 graphics cards, yielding some truly astonishing results. These early experiments reveal that implementing the upscaling technology on previous-generation AMD cards, such as the AMD Radeon RX 6800 XT, delivers significantly improved image quality in most scenarios, with only a minor dip in overall performance.
Currently, AMD has not officially extended FSR 4 support to these older graphics cards, reserving its full capabilities for the latest RDNA 4 GPUs. However, these community-driven modifications clearly demonstrate that the new technology can indeed function on a wider range of hardware, even if the implementation process isn’t straightforward for everyone.
The entire endeavor was sparked by the FSR 4 source code leak a few weeks prior. Since then, a dedicated community of modders has been diligently working to bring FSR 4 into various games using these older cards. Social media platforms like Reddit have seen numerous posts showcasing these impressive achievements. For instance, one user, nuubcake11, successfully demonstrated FSR 4 running in Cyberpunk 2077 on an AMD Radeon RX 7900 XTX graphics card.
To achieve this, nuubcake11 utilized a custom FSR 4 DDL file, which cleverly substitutes FP8 instructions with Int8. While FP8 (an 8-bit floating-point format) is optimized for the AI acceleration cores found exclusively in newer RDNA 4 GPUs, Int8 (a lower-precision 8-bit integer format) enjoys broader compatibility across older hardware, including RDNA 3. By performing this swap and integrating the patched results into the game via the open-source OptiScaler tool, FSR 4 was successfully enabled on AMD GPUs that would otherwise lack native support.
The outcome is a noticeable boost in image fidelity, accompanied by a surprisingly small reduction in frame rates. As an example, nuubcake11 observed a frame rate change from 84fps down to 79fps at 1440p in Cyberpunk 2077, with graphics settings maximized and ray tracing active, after transitioning from FSR 3.1.5 to FSR 4. This modest performance trade-off appears well worth it for the enhanced visual experience, especially considering the known limitations of FSR 3’s visual quality.
However, the modification isn’t without its quirks. In a separate instance, Reddit user bukankema managed to get FSR 4 running in Cyberpunk 2077 on an even older RDNA 2-era RX 6800 XT. This was accomplished by leveraging the GPU’s shader cores for instruction processing, as these older AMD cards lack dedicated AI cores.
This particular user reported some unusual visual artifacts, such as ghosting, specifically on Windows. These issues seem to be confined to RDNA 2 GPUs, suggesting that while FSR 4 can be enabled on older hardware, there are still some inherent limitations and potential inconsistencies in this unofficial implementation.
While AMD has yet to make an official announcement regarding FSR 4 support for its older GPUs, there’s exciting news on the horizon. The company’s upcoming FSR Redstone technology is designed to completely bypass the need for AI cores. This could potentially mean that AMD’s next-generation FSR upscaling and frame generation capabilities might run on virtually any GPU, including those from Nvidia, opening up incredible possibilities for widespread adoption.
Have you tried implementing FSR 4 on your older AMD graphics card? We’d love to hear about your experiences, whether positive or negative! Share your thoughts and join the discussion with fellow readers and our team.