I want to share a link to the following delightful paper:
Eternity in six hours: Intergalactic spreading of intelligent life and sharpening the Fermi paradox, by Stuart Armstrong and Anders Sandberg
Here is an example paragraph:
3.1.1. Data storage
It should be noted that data storage does not seem to offer much of the restriction here. The most compact method of data storage reasonably imaginable would be a diamond constructed of carbon 12 and 13, with the two types of atoms serving as bits.
This would have a storage capacity of 5x10^22 bits per gram. By comparison, the total amount of data in the human world has been estimated at 2.4x10^21 bits.
If human brains could be instantiated inside a computer, then 100 Terabytes is a reasonable estimate for the number of connections in a human brain, meaning 1 g of diamond could contain about all the world's data and the (uncompressed) population of Britain.
Which seems to me the sort of thing that should be obvious to any numerate schoolboy, except that it really isn't, until someone points it out.
If you like that paragraph, you'll probably enjoy the rest of the paper!