AMD’s Secret FSR 4 Hack Now Available for Radeon & NVIDIA GPUs

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Users don’t necessarily need the Radeon RX 9000 series to use AMD’s FSR 4, as the accidentally released DLL is functioning well.

AMD’s Mistakenly Released FSR 4 Int8 Files Can Help Enable FSR 4 on RDNA 3 and Even RDNA 2 and RTX 30 GPUs on Windows; Users See Massive Upgrade in Visual Quality Over FSR 3.1

Last month, AMD accidentally released the full source code for FSR 4, its latest upscaler that offers significantly improved visual quality over FSR 3.1. Unfortunately, this technology only works with RDNA 4 GPUs, specifically the Radeon RX 9000 series. Despite AMD officially releasing an update for Adrenalin software to run FSR 4 in games that already support FSR 3.1, users cannot do so unless they own a RDNA 4 GPU.

For RDNA 3 GPUs, this isn’t the case as it isn’t officially supported by AMD. We don’t know if AMD has plans to extend FSR 4 support to previous-gen GPUs due to slight performance regression with RDNA 3 GPUs, which lack FP8 support. However, these GPUs can technically still work with FSR 4 on Linux if forced, but the performance impacts are noticeable since RDNA 3 GPUs have to emulate FP8 via FP16.

At the moment, doing this on Windows was impossible, but the leaked AMD source code from the open-source FidelityFX SDK repository included INT8 model files. These files are supported by previous-gen GPUs like RDNA 3 and even RDNA 2 and RTX 30 series. A Reddit user used these INT8 files to compile the FSR 4 DLL and uploaded it for public use. Users have now reported that they can use this FSR 4 DLL in games through Optiscaler on Windows.

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October 8, 2025

The FSR 4 DLL reportedly works on both RDNA 3 and RDNA 2 GPUs, bringing significant visual upgrades. However, there is a noticeable performance impact, as frame processing time can be three times higher. Users typically see about 6-7 FPS lower than with FSR 3.1 at 1440p max settings with ray tracing on the RX 7900 XTX.

For example, one user demonstrated how he eliminated shimmering around grass in Cyberpunk 2077 using this method and upgraded visuals, seeing a 6-7 FPS drop but significantly better visual quality.

That said, the Balanced mode compensates for performance loss and still provides better visual quality than FSR 3.1. Remember that you need to use Optiscaler to enable FSR 4 on these GPUs, and this only works in single-player games.