AMD today released the FidelityFX SDK 1.1 to the public through its GPUOpen initiative. This update includes the source code to FSR 3.1, which should make it easier for game developers to understand the technology, and integrate it with their games. FSR 3.1 requires an AMD Radeon RX 5000 series (or later) GPU, or an NVIDIA GeForce RTX 20-series (or later) GPU, although the company recommends at least an RX 6000 series or RTX 30-series GPU, regardless of model. You get the full upscaling and frame-generation capabilities of FSR 3.1 on all supported GPUs, across AMD and NVIDIA, which is the main pull for the tech, as the rival DLSS 3 Frame Generation technology only works on RTX 40-series (or later) GPUs.
AMD FSR 3.1 builds on top of FSR 3 by introducing updates to the upscaler. If you recall, the star attraction with FSR 3 has been frame-generation, but the underlying upscaling tech had been carried over from FSR 2.2. FSR 3.1 introduces some much-needed updates to the quality of upscaling, and introduces new upscaler quality presets, including a native AA mode analogous to NVIDIA’s DLAA. These increases in upscaler quality lets you trade in quality for performance better. You can find all the resources you need on FSR 3.1 here.