Performance Impact: AMD RDNA 2 and RDNA 3 GPUs Experience ~10% Loss with FSR 4 INT8

The latest benchmarks indicate that while FSR 4 can technically operate on RDNA 2 and RDNA 3 GPUs, users should expect noticeable performance drawbacks compared to FSR 3.1.

Performance Impact of FSR 4 on RX 7800 XT and RX 6800 XT

AMD has officially designed its newest upscaling technology, FSR 4, to work exclusively with the RDNA 4, or Radeon RX 9000 series. This is primarily because these GPUs support the FP8 format, unlike their predecessors, the RDNA 3 and RDNA 2. However, with some leaked INT8 model files from AMD, savvy users have managed to get an unofficial version of FSR 4 running on these older GPU families. Although players report similar visual quality to FSR 3.1, this improvement comes with decreased gameplay smoothness.

A recent evaluation by Computer Base assessed the INT8 variant of FSR 4, exploring its performance implications for RDNA 3 and RDNA 2 users. Their findings suggest that while visual quality differences between the FP8 and INT8 versions can be significant in certain scenarios, they can also be negligible in others, varying from one game and scene to the next. Generally, it is expected that the official FP8 FSR 4 version would offer superior visual fidelity.

Screen split showing Hauptquest text in a game scene, FSR 4 auf RDNA at the bottom. — Comparison of FSR 4 on RX 9600 XT (left) and RX 7800 XT (right); Image Credit: Computer Base

In comparison tests, the FSR 4 INT8 version demonstrated superior visual results over FSR 3.1 when evaluated on the Radeon RX 7800 XT and RX 6800 XT models. Further comparisons were carried out against AMD’s RX 9060 XT, which despite being slower, exhibited minimal performance degradation—less than 3% in Quality mode at 1440p resolution when transitioning from FSR 3.1 to FSR 4.

Performance rating chart shows different RX series GPUs with FPS values; RX 7800 XT @ FSR 3 Performance leads at 86.0 FPS. — Image Credit: Computer Base

However, both the RDNA 3 and RDNA 2 GPUs experienced a significant drop in Average FPS when using the INT8 version of FSR 4. The Radeon RX 7800 XT flagged a performance decline of approximately 9%, while the RX 6800 XT recorded a similar regression near 10%. This performance loss starkly contrasts with the RX 9000 series, which maintained better performance metrics. In the FSR 4 Performance preset, the RX 7800 XT and RX 6800 XT did manage to achieve a 5% improvement over FSR 3.1; however, the gap was closer to 12-13% when compared to FSR 3.1’s Performance preset.

These observations align with previous reports indicating that the RX 6800 XT might incur a performance drop between 10-20% when adopting FSR 4 INT8, albeit with enhanced visual quality. At this juncture, AMD has not yet confirmed any plans to release an official FSR 4 INT8 for RDNA 3 and RDNA 2 GPUs, though many gamers remain hopeful for such support.

News source: Computer Base

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