assuming the server can do 100/full, and the "hub is really' a switch, 100/full may reduce collisions and retransmissions and so speed up the server
True hubs are single speed, half duplex, switching hubs are dual speed half duplex.
if possible just set everything to auto negotiate and they will find the best speed/duplex.
I tried to remain child-like, all I acheived was childish.