We've had the same problem. We upgraded to a 1 gbit network connection with succes.
I don't know why SE is transferring so much information over the network but it's cousing a lot of waiting.
A PDM program may be the solution because then SE copies the files to the local drive.
Under 'Variables' of the 'Tools' menu you see al your dimensions. You can connect the values to another value. If you're in the assy envoirement, choose 'Peer variables' instead of 'variables' and click the part you want to make master copy the value (right mouse button). Click on the part you...