Evidence mounts for AMD FSR 4 on non-RDNA 4 hardware as driver tips AMD Zen 6 iGPU to stick with RDNA 3.5

[Redaktion]

Despite impressive efficiency results in our review, AMD has now semi-officially confirmed that RDNA 4 will not make it to mobile devices in any way, not even as Zen 6 iGPUs. The good news is that this suggests AMD may eventually port FSR 4 to older generations, as the AMD Ryzen Strix Halo APU still uses RDNA 3.5 for its RTX 4060-tier iGPU performance, and the upcoming Medusa Halo iGPU is slated to deliver even more performance.

https://www.notebookcheck.net/Evidence-mounts-for-AMD-FSR-4-on-non-RDNA-4-hardware-as-driver-tips-AMD-Zen-6-iGPU-to-stick-with-RDNA-3-5.981658.0.html

[majestictodos]

damn RDNA4 is going to be insane if only 3.5 is doing the new strix halo lifting

[wrong]

you're wrong, julian

[LifePo7]

"A recent Digital Foundry interview with Eurogamer claimed that some version of FSR 4 could be run on the PS5 Pro, which uses RDNA 2 GPU hardware, meaning it should be possible to run FSR 4 on regular consumer-grade PC hardware as far back as RDNA 2, as well. "

This is misinformation, PS5 pro has a customized block for ML with 300TOPs (no sparsity)

RDNA2 GPUs has no chance of running this.

[Kaotik]

You've completely misunderstood the DF interview. Sony specifically says they want to build something LIKE FSR 4 for the PS5 (Pro), but it can't run FSR 4. FSR 4 uses FP8 which older hardware simply doesn't support, not even PS5 Pro which ML hardware is pure 3x3 convolution acceleration, which is less flexible than even RDNA 3's WMMA support, let alone RDNA 4's enhanced WMMA + SWMMAC. IF it gets ported to older hardware, RDNA 3 would be the only one in theory which might have a shot at it, but even for it would be 4 times as heavy as it is for RDNA 4

[opckieran]

What a shame to think RDNA4 will be desktop-only.

[Bummer]

Bummer, AMD has over 1 year time to move RDNA 4 to Zen 6. I guess it takes more time? I don't think AMD is doing it on purpose, although even Zen 5 still only has RDNA 2 (thanks AMD for giving me another reason to not upgrade from my Zen 4). I understand that in a desktop CPU, its iGPU matters much, much less than for mobile, as a desktop gonna have a dedicated GPU anyway.

According to:

computerbase.de/artikel/grafikkarten/amd-radeon-rx-9070-xt-rx-9070-test.91578/seite-9#abschnitt_energieeffizienz_in_fps_pro_watt

the power efficiency improvement of 7900XTX to 9070XT is only 7%, but 70% if using a FPS limit!

Indeed, supposedly FSR4 uses FP8, which is only in RDNA 4.

Someone said:

The current FSR4 is a hybrid between a CNN and a Transformer model from a whitepaper review with sources here, and in theory a FSR4-lite can exist by not utilizing the Transformer at all. Essentially near-parity to DLSS3 without the ability for the FSR-Lite to use the Transformer layer, but only if there's additional work done to resolve the sharpening issues.

Transformer model needs FP8 that RDNA 3.X lacks, but the dedicated existing INT8 might be utilized better with better model training in the future. Or even a Transformer model that somehow uses those same INT8 fixed-fuction hardware to run.

So maybe INT8 in RDNA 2 and RDNA 3 can be utilized for FSR 4 (the performance and/or quality could be different tho).