In what important respect does the conductivity of a conductor differ from that of an intrinsic Semiconductor.          

It is well known that the conductivity of a conductor is much superior to that of the intrinsic semi-conductor. In an intrinsic semiconductor the number of electrons in the conduction band is eqivalent to the number of holes in the valence band at room temperature and there exists an Energy Gap among the conduction band and valence band which doesn't permit charge carriers to move freely and therefore their conductivity is low. 

A conductor such as a metal has high conductivity. The conductivity of a semiconductor is commonly intermediate, but varies widely under dissimilar conditions, such as exposure of the material to electric fields or exact frequencies of light, and, most important, with temperature and composition of the semiconductor material.