Are you aware of that secure pw hashing comes with a cost factor and that the cost is linear with the size of the input to the hashing algorithm?
EDIT: Down voters. What pw hashing algo are you using instead of BCrypt or similair?
EDIT: Down voters. What pw hashing algo are you using instead of BCrypt or similair?
That said, a few MB is a lot for one client to post if you have a significant amount of traffic. Just hash client side first.