Theoretical speed could not be reached(help)

[nicheng]

THE THEORETICAL SPEED CANNOT BE REACHED, AND THE ACTUAL SPEED IS ONLY 1700H/S， Because of my hash value is $2a$10$ So I chose to use it -m 3200 in use -b Look at the theoretical velocity as  12889 H/s There is too much difference from reality Even if I use -w 3 Still not improving Please help me