Thanks, that makes sense. I was using a SuperSampling value of 3, so I guess it was overloaded, but when I watch my ram usage I don't see it go much above 8 during the render startup. I did notice just before the AP calculation, it lists a buffer size: Num buffer layers: 4 Master buffer size: 1.267 ...

Why does aperture diffraction fail when rendering above 2400 pixels in width? I have 32gb of ram, but it still says it runs out of buffer. Is there something that can be changed to increase the buffer?

-Lightrik