Please be more precise with your question, e.g. which algorithms you are talking about for which applicatio, why you need to know data rates and why you think there must be some "requirement" for those rates.

I strongly advise you to have a read on Daniel J. Bernstein's document about the era of post-quantum cryptography: http://www.pqcrypto.org/www.springer.com/cda/content/document/cda_downloaddocument/9783540887010-c1.pdf

Please be sure to fully understand Chapter 4.

If I had to guess what you mean by your question, I would quote Bernstein:

A modern stream cipher can run on any commonly available CPU, and

generates gigabytes of stream per second on a $200 CPU. Quantum cryptography generates kilobytes of stream per second on special hardware

costing $50000.

So it is not about what kind of data rates quantum cryptography "requires". Modern ciphers also do not have a data rate requirement, you just make use of the data rate available to you through your hard- and software.

It will be more about how to build inexpensive hardware for quantum cryptography in the future to reach high data rates.