Phone line network and Zone Alram

[Fuelrod]

I just upgraded my home phone line network from the 1 Mbit standard to the 10 Mbit standard. After benchmarking the network is shows I am only getting about 3 Mbit through put. I track down the problem to Zone Alarm. If I turn off Zone Alarm I get 10 Mbits/s. Is this normal? I did not think firewall programs slowed down network traffic that much. Has anyone seen this problem with other firewall programs?