Why VRayAlSurfaceMtl's SSS2 colors have different render times

[flat]

Why is the rendering time (sample rate) so different just by changing the SSS2 color of VRayAlSurfaceMtl in the attached scene?

Setting the SSS2 color to dark red or brown is slower, and light pink or brown is faster to reduce samples.

RGB doesn't make a big difference, and using a bucket sampler.

Confirmed with V-Ray 5, Update 1

[tashko.zashev]

Hi,

I'm not sure if this is an expected behavior or an issue right now. Will need to do some more tests because it seems to be slower when using clear colors indeed.
Thank you for this report!

[flat]

Thank you for your confirmation. I'm happy to know the cause.