Hairs with motion blur, Render times!? (Cycles render) in b3d Beta 2.8


Does anybody rendered some fully covered animal with hair with mblur and Cycles?

Im testing it these days but compared non blurred version (without mblur) it takes insane render time! It not 2x more it seems like 8-10x longer render times!

I ve tried to optimize the hair shader not just using PrincipledHair (probably most render expensive) but mix shaders like Diffuse, Hair etc for different lightpaths (using LightPath node to select which shader to use for which ray types) but it didnt solve it all (about 10-30 percent speed gain but loss of visual quality).

If someone has experience with hair render optimizations would be cool to hear it! Thanks a lot for any idea guys!