AMD Faces Backlash After Accidentally Leaking FSR 4 Code
AMD made a major blunder in recent days by mistakenly disclosing the full libraries and source code of FSR 4 on its GitHub repository via the AMD OpenGPU project. Despite taking it offline afterwards, modders had already taken notice.
The files contained information about an INT8 version of FSR 4, a lighter version that could work on older RDNA 2 and RDNA 3 GPUs. Currently, AMD has no plans to release FSR 4 for older Radeon cards. What’s more surprising is that the PS5 and PS5 Pro, based on RDNA 2, use an INT8 version of FSR 4, which Sony refers to as “enhanced PSSR upscaling.”
Modders have already removed and patched the INT8 version of FSR 4 for Radeon RX 6000 and 7000 graphics cards
When AMD unveiled FSR 4, or FSR Redstone, the company clearly stated that it was specifically designed for its latest RDNA 4 GPUs in the Radeon RX 9000 series. The GitHub leak showed that the extended INT8 iteration of FSR 4 could effectively run on RDNA 2 and RDNA 3 GPUs, excluding users of the RX 6000 and RX 7000 series from this technology.
However, this did not stop modders, who removed the libraries from the repository before AMD took them down and began patching their games to bring the INT8 FSR 4 version to RX 6000 and RX 7000 series GPUs.
PlayStation 5’s Enhanced PSSR 2.0 Uses INT8 Version of FSR 4
Sony has received and implemented the enhanced version of PSSR, often called PSSR 2.0, in Resident Evil: Requiem. In a recent interview, Mark Cerny, lead system architect of PlayStation, discussed how the new PSSR technology is linked to AMD.
Mark Cerny mentioned the technical differences between FSR 4 and the new PSSR, stating: “FSR Redstone and the new PSSR have somewhat different implementations due to the underlying hardware, for example, FSR Upscaling uses 8-bit floating point, while PSSR uses 8-bit integers.”
He also explained that the core technology remains the same, but the training process varies to adapt to each platform, namely PC and PlayStation 5. He continued, “In practice, the same model is used, but it is trained on different data, for example, if targeting a fixed 2:1 upscaling, the training data used only concerns that upsampling rate, and this different training results in different parameters… Not seeing much difference in the results, the various updated flavors of FSR Upscaling are quite close to the new PSSR.”
This confirms that PSSR 2.0 on the PS5 Pro actually runs the INT8 version of FSR 4 that AMD accidentally leaked in its GitHub libraries. To make matters worse, AMD has been silent on the issue, and it seems Team Red will not bring FSR 4 to older Radeon GPUs, making purchasing a RX 9000 series GPU the only way to officially get FSR 4 support from Team Red.
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