Cycles Particle Carpet renders different in CPU and GPU mode

I need somebody to confirm a bug. I get different results from Cycles rendering a particle carpet. The GPU result is fine. But the CPU result shows odd shading.

It is already reported since several weeks. But the devs couldn’t reproduce it so far. And Dingto is about to close the bug report since nobody could confirm it.

The guess is that it is something special with my current processor. A Intel i7 4770 Haswell. So when you have the same processor, and run Win 7, could you please have a look if the bug happens to you too?

First introduced was the bug with Blender 2.71. Blender 2.70 renders fine on both, CPU and GPU. In Blender 2.71 i get a different result though. The CPU version of the rendering shows odd shading. See screenshot. It still happens with newest build from Buildbot, Date 2014-09-10

The bug report can be found here:

Example scene can be downloaded here:


Sorry mate I have a 4770 and a 780 ti, and I get exactly the same image from CPU or GPU. I’m using the official 2.71 btw.

Many thanks for having a look Wig42 :slight_smile:

So not the processor in general. Interesting. Seems that it’s one of those uncatchable bugs that just happens to a few. Well, it was at least worth a try :slight_smile:

no issues here…
blender 2.71
i7 930
GTX 780

Thanks cegaton :slight_smile: