Computers are famous for being able to do complicated things starting from simple programs.
Indeed, as the above calculation indicates, to take full advantage of the memory space available, the ultimate laptop must turn all its matter into energy.
There are considerable advantages to using many degrees of freedom to store information, stability and controllability being perhaps the most important.
We have a picture for how complexity arises, because if the universe is computationally capable, maybe we shouldn't be so surprised that things are so entirely out of control.
One of the things that I've been doing recently in my scientific research is to ask this question: Is the universe actually capable of performing things like digital computations?
In order to figure out how to make atoms compute, you have to learn how to speak their language and to understand how they process information under normal circumstances.
If you wanted to build the most powerful computer you could, you can't do better than including everything in the universe that's potentially available.