Matrioshka brain

A matrioshka brain[1][2] is a hypothetical megastructure of immense computational capacity powered by a Dyson sphere.

It is an example of a class-B stellar engine, employing the entire energy output of a star to drive computer systems.

The innermost Dyson sphere of the matrioshka brain would draw energy directly from the star it surrounds and give off large amounts of waste heat while computing at a high temperature.

For this reason, Matrioshka brains with more nested Dyson spheres would tend to be more efficient, as they would waste less heat energy.

[9] Jupiter brain is related to the idea of the hypothetical material computronium, which could be enmassed to sizes of entire planets and even stars.