Upgrade your router if anything. Go from 10/100 to Full GigE=1000 between clients.

In the end your router is only putting out 6-10mb from your cable modem (you have one and not FIber?) So it really doesn't matter about the network performance as it's all throttled down to the lowest common denominator when it exits your LAN and connects to Blizzards servers.

This card is cute, but in the end it's just a 'cpu' on a network card, my 3C905 has one of those too.