Silent_Buddha
Legend
I don't have an answer unfortunately. It's just something I've been noticing. @Dictator might be able to chime in on this. I think he states in his Metro video that the RT is significantly more taxing on the CPU with the latest version versus the older 2019 RT variant.
I mean, perhaps it's because they don't trust async compute on PC? I'm not sure. It is quite slow to go back and forth between CPU/GPU.
They could do everything GPU side, I mean, that would make sense, but perhaps it's not trivial to do -- more time to bake this type of feature as there are more challenges to overcome.
It might be that instead of relying on NV's black box for all things BVH related, they are now building the BVH on the CPU for all platforms in order to have it be uniform for all platforms. Or something similar. That could explain why the CPU cost of RT has gone up.
It is theoretically possible if RT involves a hit to the CPU in such a scenario that this could be a potential double whammy that "might" lead to better RT performance on XBS-X (slightly faster CPU versus a non-throttled PS5, wider compute and more bandwidth) in the future. But it's still far too early to say, and I'm still uncertain we'll ever be able to pin any performance differences to better or worse handling of RT. Especially as other parts of the architecture will come into play during any rendering scene.
Regards,
SB
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