My understanding is that the people behind this work are writing a paper on it, which when done will presumably make everything much more explicit than the slides do.
> Anders Sandberg, Stuart Armstrong, and their co-author Milan Cirkovic published a paper outlining a potential strategy for advanced civilizations to postpone computation until the universe is much colder, and thereby producing up to a 10^30 multiplier of achievable computation. This might explain the Fermi paradox, although a future paper from FHI suggests there may be no paradox to explain.