Brain

Human brains can be considered to be relatively weak as they only have a fixed amount of storage available. Once that limit is reached, they're going to have issues. Some estimate this limit to be in the range of terabytes whereas others in the millions of gigabytes. Whatever the case, at least their brain is optimized in a way that most of the useless data isn't wasting space.

We however don't recommend using human brains as they are way too inconsistent to be able to be properly used to store data.