You reasoning seems to be something along the line of:
efficiency(QC) > efficiency(non-QC) > efficiency(Human).
therefore efficiency(QC) > efficiency(Human).
therefore. QC ≠ Human.
However, the power of a computational device isn't measured solely by its efficiency. A trivial example is the following:
A hand calculator is much more efficient at multiplying 34612342342349287423 * 4372834021347826340234 than a human mind is, yet the human mind can solve a wider class of problems than hand calculators.
"Quantum mind" arguments usually center around the idea that the human mind can solve a wider class of problems than classical computers (see undecidable problems) or that human consciousness has properties that can't be explained with classical computing models (i.e Turing machines). It is then argued that Quantum computers might be able to solve these problems or duplicate these properties that classical computers can't, and therefore the mind must be a Quantum computer.
The real problem with quantum mind arguments is that the consensus among computer scientists is that Quantum computers cannot solve any of the problems that classical computers can't. They are likely more efficient that non-QC, but that's it, they can't solve any of the undecidable problems. So if a human mind is indeed more powerful that a classical computer, quantum computing isn't the answer.
See this answer for more details about one of the more prominent quantum mind arguments.
As Conifold points out in the comments, beside the computer theoretical considerations I mentioned, there are physical arguments against Quantum mind theories (See Max Tegmark's argument against Quantum brains).
Interestingly enough, Max Tegmark seems more recently to seriously explore the notion that concsiousness is a state of matter, so I don't where he stands exactly on the question nowadays.