On my GUIminer its says I'm mining at 76.4 Mhash/s and it maintains that but sometimes goes ranges from 71.4- 76 but usually its maintains at 76.4 Mhash/s.  When I check my account and go to the workers section its says that I'm mining at 47.306 Mhash/s.  Is there something wrong with my setup? or is that how it is normally?