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When rendering a scene, the colours look very different when rendering using the GPU (NVIDIA GeForce GTX 680) vs. rendering using the CPU. There is a lot more red and the other colours look a lot more saturated on the GPU.

I'm using the Cycles rendering engine in Blender 2.81a on Linux.

The shader uses a complicated formula and plugs the results into the color and density values of a volume scatter material.

What you see is called Mandelbulb.

CPU: CPU

GPU: GPU

Any ideas what could be causing this? Can anybody confirm that this issue also exists on their GPU and is not just related to my specific GPU model/driver version?

Here is my .blend file: http://pasteall.org/blend/index.php?id=52870

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  • $\begingroup$ Can confirm I'm getting the same issue with i7 7700 and GTX 1070. Not quite sure why though. $\endgroup$ – stphnl329 Feb 6 at 2:23
  • $\begingroup$ My 2 cents is that it is not a problem of colors but a problem of calculations. My best bet is that your cpu stops the calculation on one of the first loops rather than the gpu which goes through all of them, giving different results when the colorramp and density are applied to the volume shader $\endgroup$ – Gorgious Feb 6 at 12:54
  • $\begingroup$ Maybe the floating-point numbers passed around in the shader have a different precision on the CPU and GPU leading to different floating-point rounding errors and therefore different results. Anyways, I'll just render this on the GPU then. $\endgroup$ – Luflosi Feb 10 at 14:07

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