  We investigate the issue of speed-up and the necessity of entanglement in
Grover's quantum search algorithm. We find that in a pure state implementation
of Grover's algorithm entanglement is present even though the initial and
target states are product states. In pseudo-pure state implementations, the
separability of the states involved defines an entanglement boundary in terms
of a bound on the purity parameter. Using this bound we investigate the
necessity of entanglement in quantum searching for these pseudo-pure state
implementations. If every active molecule involved in the ensemble is `charged
for' then in existing machines speed-up without entanglement is not possible.
