Two days ago, AMD published its FidelityFX SDK 2.0 via its GPUOpen project, which included FSR 4 upscaling and FSR 3.1.5 frame generation support. But, during the process, the brand unintentionally released the full source code of FSR 4 on GitHub. As usual, the internet was quick to capture screenshots and collect as much information as possible before AMD had time to react.
With the genie out of the bottle, users began combing the collected data, uncovering sneak peeks into FSR 4’s inner workings. One of the biggest discoveries is undoubtedly the inclusion of an 8-bit integer (INT8) library, which uses fewer resources at the cost of precision, hinting that AMD was strongly considering or was working on a version of FSR 4 compatible with older Radeon RX 7000 GPUs.
Since the Radeon RX 9000 chips already feature the AI capabilities required for the regular FSR 4 implementation, this alternative version is most likely meant for older hardware, which currently lacks an equivalent upscaling technology. Thus, this FSR 4 ‘leak’ confirms that AMD has at least tried to make FSR 4 work on RDNA 3 GPUs as it promised during the initial launch of the feature.
Unfortunately, these files aren’t indicating whether AMD has stopped or is continuing this project. The good news is that with the source code now in nature, modders will undoubtedly leverage it to build mods capable of enabling FSR 4 on old GPUs. While these are unlikely to deliver the same quality and performance as the proper support offered by RDNA 4’s FP8 processing, they will at least give users another option to choose from.
That said, the best results will only be possible with AMD’s intervention. If the company ends up releasing an official FSR 4 variant on RDNA 3 and older GPUs, you can expect it to offer the best quality and performance, similar to what Intel has done with its XeSS DP4a, which doesn’t require Arc GPU’s XMX hardware AI-accelerators. This may even open the way to support some features from the upcoming Redstone project.
Either way, this is a good thing for gamers. If not AMD, the modding community will do something with it, because seeing what they managed to do with so little insight into FSR 4’s inner workings, everything is possible.
