It's an old project, I don't really remember why I set the material so. I probably had an "artistic" reasonabstrax wrote: Why don't you use just one specular material for the droplets?
Regarding the speed drop: How does it compare to 3.01? 2.59 doesn't support instances which is probably the main reason why it's faster.

In 301 it renders in 13:22, so 42 seconds slower than 302. Instances are not used in any of these (note at the bottom of the screenshot it says 1 meshes). But as I understand the new framework that allows instances causes some slowdown even if instances are not used?