My Render View looks completely different from my saved render. Why is that? Same file, same scene, same render node, same everything (apparently not?)

First guess; render view always uses a raytrace engine. If your Mantra ROP is set to a micropolygon renderer, the result can be quite different (depending on sampling settings).

eetu.

Relative Paths?

Yes eetu, it seems to have to do with that but I'll have to set the samples up to 512 though to get it looking as smooth as the renderview. Something weird going on there.

This looks like a shadur antialiasing problem to me. I belive the reason why the render view is smooth is because the shadur is frequency clamping all of that odd splotchy noise out of the render, leaving you with noise that returns the median value.

The mechanisms for antialiasing high frequency patterns behave differently for raytracing vs. micropolygon rendering, so that could be leading to the difference in the images.

Try eliminating unnesscesary high frequency patterns from your shadur.