bump maps slower then displacement?

[Long John]

can it be that bump maps are slower then displacement?

i have a material with blurry reflections on a object where i use displacement and because i thought maybe bump mapping will be faster i removed the displacement and used the displacement image as bump map.

now it looks like (the image is not finished yet so i can ntot say for sure), that bumps render slower.

i thought that displacement should be slower, not?

[flipside]

Displacement should be slower if you render with GI because then the solution will be more complicated where the displaced parts are. Without GI and only regarding to reflections, I don't think displacement will be slower to render than bumps.

[RErender]

I have not done extensive testing but I have noticed that displacement is often faster than bump maps. My guess is that V-Ray prefers the actual geometry over calculating how the bump map would effect the bounces. It would be great if Vlado would give us some clarification on this.

[flipside]

Yeah that's possible that it's just easier for reflection calculations to have real geometry. Sounds logical!