see also <a href="http://aleph.se/andart2/megascale/just-how-efficient-can-a-jupiter-brain-be/" rel="nofollow">http://aleph.se/andart2/megascale/just-how-efficient-can-a-j...</a> and <a href="https://www.gwern.net/docs/1999-bradbury-matrioshkabrains.pdf" rel="nofollow">https://www.gwern.net/docs/1999-bradbury-matrioshkabrains.pd...</a> <a href="http://aleph.se/andart2/megascale/energy-requirements-of-the-singularity/" rel="nofollow">http://aleph.se/andart2/megascale/energy-requirements-of-the...</a>