The scattering actually uses small amount of memory :- ). But takes really long time to render noise-free (if you region crop onto that part, the ray/s drop to like 1/10th). Perhaps because of translucency but I don't remember if it's even translucent in the end...
The carpet that you see below, is 3dsMax Hair&Fur, with pathetic amount of hair (LOT less then million, maybe not even few hundred thousands?) takes like 5 damn minutes of pre-pass before rendering and eats like... 60 GB? I dunno, absurd number.
Utter total stupidity, time to try Ornatrix.