  We consider quantum formalism limited by the classical simulating computer
with the fixed memory. The memory is redistributed in the course of modeling by
the variation of the set of classical states and the accuracy of the
representation of amplitudes. This computational description completely
preserves the conventional formalism and does not contradicts to experiments,
but it makes impossible fast quantum algorithms. This description involves the
slow down of quantum evolutions with the growth of the dimension of the minimal
subspace containing entangled states, which arise in the evolution. This slow
down is the single difference of the proposed formalism from the standard one;
it is negligible for the systems from the usual experiments, including those in
which many entangled particle participate, but grows rapidly in the attempt to
realize the scalable quantum computations, which require the unlimited
parallelism. The experimental verification of this version of quantum formalism
is reduced to the fixation of this slow down. In all probability the memory of
the abstract computer simulating quantum processes is limited by 10-20 qubits,
so it iss possible to use the exiting computers for this aim.
