This simple smoke simulation was made following this excellent Applied Houdini course, and took ~30 hours to render in Mantra for 120 frames utilising some 16GB RAM. It’s clear why people recommend having so much RAM for Houdini work.
The instructor behind Applied Houdini is really really good and I’d love to have all his courses, but at $830 USD for the set that feels pretty steep. Buying some single ones might make sense depending on how I’m progressing, if nothing else just because it feels good to support people who are making such good content.