AMD accidentally posted FSR 4's source code as part of its FidelityFX SDK 2.0 launch

With the release of AMD's FidelityFX SDK 2.0, FSR 4 is finally available for all game developers, with integration available via signed DLLs. And to make things super easy for developers creating titles with Unreal Engine 5, this update also includes an Unreal Engine 5 plugin for developers to add FSR 4 support in games.

2

AMD's FSR 4 is the latest iteration of the company's FidelityFX Super Resolution technology that moves to an AI solution similar to NVIDIA DLSS. As such, it's currently exclusive to AMD's RDNA 4 desktop GPUs, like the Radeon RX 9070 XT, which include advanced AI hardware. Per our reviews and hands-on time with FSR 4, it's safe to say that it presents a massive leap forward in image quality compared to FSR 3, and finally closes the gap between FSR and DLSS.

However, unlike previous versions of FSR, FSR 4 is not officially 'open source' yet, with code available to all developers. Well, with the release of FidelityFX SDK 2.0, it was for a moment, as AMD briefly released the FSR 4 source code before taking it down.

And things get a little interesting with the above screenshot from Videocardz, which indicates that AMD was or is working on multiple versions of FSR 4, one that is FP8-based (which is the version currently available for RDNA 4 GPUs) and one that is INT8-based. The latter indicates that AMD is looking to bring FSR 4 to more hardware, which could include the company's RDNA 3-powered Radeon RX 7000 Series. Or, the source code depository that was briefly shared merely contains AMD's attempts to get its more complex AI version of FSR to run on older Radeon hardware.

In addition to FSR 4, AMD's FidelityFX SDK also lays the groundwork for all future AI or machine learning technologies that are coming soon - like FSR Redstone, which includes an AI-powered version of FidelityFX Frame Generation. With updated DLLs, FidelityFX SDK 2.0 also makes it easy for AMD's Radeon and graphics software to override current versions of FSR 3 or 4 with the latest version of FSR 4, similar to how NVIDIA's DLSS Override works.

AMD has also confirmed that AMD FSR 3.1.4 Frame Generation will automatically update to FSR ML Frame Generation. That is, if you've got an RDNA 4 GPU, as AMD adds that the AMD FidelityFX API will automatically select AMD FSR 3.1.5 for older Radeon hardware.