Yes, it does. :-) Something like 3-4 times with glass added - from 3 minutes to 12 for my banner, but then, it was quite close to the camera. And it increases even more if you increase TIR and ... whatever's immediately above TIR. Ray depth? Anyway, that had value of twelve with TIR of 7, and my banner was rendering for 32 minutes plus antialiasing. 1000 x 250. I think that all depends on the closeness to the camera, of course. Another thing, if you search the forum, you'll find a post or two about subsurface scattering that can be faked with this technique.

-- erlik