Hey fellow Blendy people,

I'm running some benchmark comparisons between various render engines involving a lot of small, simple scenes.

Anyway, on my test scene for volumetrics, I'm noticing a large discrepancy between GPU and CPU rendering. All other settings in the scene are identical. Any ideas? I've never come accross this before, though to be fair I rarely render on CPU.

As you can see from the picture below, it's as though the volumetric density is different.

Example of Volumetrics discrepancy

Any thoughts on this would be greatly appreciated.


  • 2
    $\begingroup$ Does this answer your question? Why do volumetrics render noisier when using GPU then when using CPU in Cycles? $\endgroup$ – Robert Gützkow Dec 19 '19 at 16:41
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    $\begingroup$ It looks like more of a discrepancy with density than a noise difference. In the GPU render the background is obscured by the fog, but the CPU render isn't behaving in the same way. $\endgroup$ – BlenderBrit Dec 19 '19 at 21:28
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    $\begingroup$ You're right, seems like it. Is that light a circular area light pointing at the camera or something like a point light or mesh light? $\endgroup$ – Robert Gützkow Dec 19 '19 at 21:35

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