On a philosophical note:
All computers are built of circuitry that can perform a discrete set of operations, which can be reduced to the NAND (logical not-and) operation. Rigourous mathematical analysis shows that systems built from arbitrary numbers of such parts can compute a set of mathematical functions. So in a sense, all computers using a sufficiently rich 'language' (containing if-then and a loop instruction) are equally powerful in terms of what can be computed in finite time. Hilbert, a century ago, along these lines formulated a mathematical challenge to proof that a simple formalizable system / 'computer language', arithmetic, is free of internal contradictions.
Kurt Godel came with an answer to Hilbert's problem that surprised everyone: he gave a proof that for every formal system (such as a decription of the reality of aviation, formulated in computer languages) there are theorems that are true but that are not algoritmically provable within the formal system. This means that there always exist correct conclusions about how to fly a plane that AI cannot draw.
An interesting point is that for us humans, using 'insight', it is possible to 'see' that these theorems are true. Godel's theorem puts a fundamental limit on what AI can do, even in a world where software is perfect.
To get a flavour of Godels theorem:
http://isites.harvard.edu/fs/docs/ic...les/boolos.pdf .