AMD's FSR 4 upscaling technology, initially claimed to be exclusive to RDNA 4 GPUs, contained an INT8 implementation that later appeared as Upgraded PSSR on the PlayStation 5 Pro. The company accidentally published libraries suggesting FSR 4 support for RDNA 3 and RDNA 2 GPUs, which modders subsequently used to enable the technology on Radeon RX 7000 and 6000 graphics cards.

Sony's Mark Cerny revealed in a Digital Foundry interview that FSR Redstone and PSSR have different implementations due to hardware differences. While FSR uses 8-bit floating point, PSSR employs 8-bit integer processing. Cerny explained that the same model is used but trained on different data for specific upscaling ratios, resulting in different parameters.

The INT8 version found in the leaked libraries appears to have been a compatibility implementation that AMD later refined for console hardware. Cerny noted that PC gamers sitting closer to monitors have different visual expectations compared to living room console users, explaining why FSR and PSSR target slightly different goals despite their technical similarities.