Now I mess with HDRI maps
The attachement took 44(!) minutes to render even though the skylight shadow casting was off and there was a small overall amount of rays.
For some reason, when I turn on the skylight shadow casting the whole thing crashes when i try to render... That happens in any LFS scene, but everything's ok when I use some simple scene (like a mirror ball)
...D'oh now the FXO scene's corrupted