Mike, I have used Directway 4000 in the same configuration that you are describing. The Direcway 4000 connects to a host computer via USB connection. The host computer acts as a server and distributes the internet to the other computers via Microsoft ICS bound to the network adapter. The other computers on your network are considered 'clients' in this configuration. Downloading a program fron Direcway called 'Lan Client Configuration' (LCCU) will optomize the settings on the client computers so they will operate as fast as the host. I had the same problem you described and this fixed it for me. The good thing about LCCU is that it saves your old settings and you can execute the program and select 'restore' if things go awry. Do NOT run this program on the host machine.
I have recently switched to Direcway 6000. This system is self-hosted and requires no host computer. The modem uses network (cat5) connectivity and allows you to hook directly into a router/hub/switch. I use a switch if anyone really cares. I plugged the modem into a standard port on the switch and it works. No configuring or settings were needed. I understand that when using a hub/router, some configuring is needed if you use the WAN connection. This is where my knowledge ends and I get off this train.