A surprising AMD slip-up has sparked fresh excitement around FSR 4, and it’s shining an unexpected spotlight on the technology powering Sony’s latest PlayStation upscaling.
In recent days, an AMD GitHub repository briefly exposed FSR 4 libraries and source code tied to the AMD OpenGPU Project. Although the files were quickly taken offline, they were visible long enough for the community to download and dig through them. The most attention-grabbing discovery wasn’t just that FSR 4 materials appeared publicly at all—it was evidence of an INT8 (8-bit integer) build of FSR 4 that looks capable of running on older RDNA 2 and RDNA 3 GPUs.
That’s a big deal because AMD has been positioning FSR 4 (also referenced as FSR Redstone) as a feature designed specifically for its newest RDNA 4 graphics cards, particularly the Radeon RX 9000 series. In other words, the official message has been: if you want FSR 4, you’ll need newer hardware. The leaked files suggest the real-world situation may be more complicated, thanks to this lighter INT8 variant.
Modders didn’t waste any time. After pulling the leaked libraries, some began patching games to get the INT8 FSR 4 build running on Radeon RX 6000 and RX 7000 series graphics cards—GPUs based on RDNA 2 and RDNA 3. While this isn’t official support and results can vary, the very fact that it’s possible has reignited debate over why FSR 4 is being held back from older Radeon owners in the first place.
The PlayStation angle makes this story even more interesting. The PlayStation 5 and PlayStation 5 Pro are based on AMD RDNA 2 technology, yet Sony has rolled out an upgraded version of its PlayStation Spectral Super Resolution upscaling solution—often referred to as “upgraded PSSR” or “PSSR 2.0”—with its use highlighted in Resident Evil: Requiem.
In an interview with Digital Foundry, PlayStation lead architect Mark Cerny explained the relationship between AMD’s work and Sony’s PSSR. He described how the implementations differ based on hardware, noting that FSR upscaling uses 8-bit floating point, while PSSR uses 8-bit integer. He also clarified that the underlying model is essentially shared, but trained differently depending on the target platform and use case, such as training specifically for a fixed 2:1 upscale ratio. According to Cerny, the end results between the various updated FSR upscaling “flavors” and the new PSSR are not dramatically different.
Taken together, that’s strong confirmation that PlayStation’s upgraded PSSR is effectively leveraging the INT8 approach—matching what was spotted in the leaked FSR 4 materials. It also fuels frustration for PC players with RDNA 2 and RDNA 3 cards: if a similar INT8-based technique works well on PlayStation 5 hardware, why isn’t there a clear path to official FSR 4 support for Radeon RX 6000 and RX 7000 owners?
So far, AMD hasn’t publicly addressed the leak or clarified whether the INT8 build represents a future plan, an internal experiment, or something that will remain off-limits outside of RDNA 4 products. For now, Radeon users who want guaranteed, official FSR 4 support may still be pushed toward the RX 9000 series—while the modding community continues to explore what’s possible on older hardware.
