So I wanted to share a rendering tip I found out, maybe you all already know about this, and if so great! If not then here is what I recently learned.
When rendering a scene, a room for example and let's say you have a living room, with 2 couches, a chair a rug and a bookshelf with books and a lamp
So if you turn off any object in your scene that is not directly in your viewport it will dramatically speed up your render.
Because Iray calculates everything in your scene even the stuff that is not being rendered. So when you turn off the stuff in the scene that is not in the viewport, iray does not calculate it.
This even helps when rendering people. if you turn off the different parts of the limbs that are not being rendered it can help a huge amount
Anyway, just thought I would pose this.