AMD FSR 4 INT8 Simulation on Xbox Series X Reveals Potential Gains in Image Quality and Frame Rate

AMD FSR 4 INT8: A Glimpse into Upscaling Technology

Recently, a notable development surrounding AMD’s FidelityFX Super Resolution (FSR) came to light after the accidental leak of its source code. Modders have successfully adapted the AMD FSR 4 functionality for GPUs that do not employ the RDNA 4 architecture, such as the Radeon RX 9000 Series, which debuted earlier this year. The official version of FSR 4 utilizes FP8, the 8-bit Floating-Point format. However, the leaked INT8 variant employs the 8-bit Integer Fixed-Point format, which is more compatible with a broader array of contemporary GPUs.

The Choice of FP8: Performance vs. Quality

AMD’s decision to opt for FP8 over INT8 in FSR 4’s public release was strategic. The FP8 format significantly enhances dynamic range, providing better model accuracy and visual stability. Richard Leadbetter from Digital Foundry has conducted extensive tests comparing the performance and quality of both versions on non-RDNA 4 hardware.

Quality Assessment and Performance Issues

In his analysis, Leadbetter highlighted stark differences between the two formats. The INT8 version, while operational, suffers from aliasing and temporal artifacts, which are exacerbated with the recent Adrenalin driver (version 25.9.1); users are advised to revert to driver 23.9.1 for a better experience with the INT8 variant.

Despite the downsides, FSR 4 INT8 does deliver a noticeable quality advantage over its predecessor, AMD FSR 3. The drawback is a marked decrease in performance: while the new version offers some improvements, it remains considerably slower. It’s worth mentioning that, although the PlayStation 5 does not support the INT8 format, the Xbox Series X is fully compatible due to its RDNA 2 feature set.

Benchmark Comparisons: FSR 4 INT8 vs. Competing Technologies

To simulate the performance of FSR 4 on the Xbox Series X, Digital Foundry utilized an RX 6700 GPU, testing it with the Horizon Forbidden West benchmark. Results indicated that FSR 4 INT8 trails behind both AMD FSR 3 and Intel XeSS in performance metrics. When set to Performance mode, it achieves merely a 28% uplift compared to native 4K resolution, while XeSS Balance manages a 15% improvement, and FSR 3 Performance mode sees a 29% increase.

In a different benchmark involving Alan Wake 2 at 1440p, FSR 4 Performance mode did yield a slight edge in frame rates over FSR 2 Balance mode (approximately 4% faster) and produced a cleaner image, demonstrating its potential despite lower base resolution processing.

Future Outlook for AMD FSR 4 INT8

While FSR 4 INT8 shows promise for specific scenarios on the Xbox Series X, the broader gaming landscape may not fully capitalize on this technology due to the lack of support on cross-platform titles, particularly given the limitations of the PlayStation 5.

Digital Foundry’s analysis also delves into the performance ramifications of using this version on the Steam Deck, aligning with previous reports indicating substantial image enhancements at the cost of performance in various titles, including Cyberpunk 2077. Furthermore, AMD hinted at potential updates for FSR 4 in the upcoming Fall season, suggesting ongoing efforts to enhance the technology:

We look forward to more updates to FSR4 this Fall that will continue to improve gamers’ experiences.

Although this statement isn’t a definitive confirmation, it implies that future iterations of FSR 4 INT8 might exhibit optimizations that enhance viability for RDNA 2 and RDNA 3 hardware configurations.

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