[=[DOA]=Meat Grinder]

I have a cable modem and dsl. Whether I play single player or multi, my fps drops every second with a modem turned on. Unplug or shut off modem, and my fps doesn't dip. Why would this affect single player too? It does the same thing with Wolfenstein. And I can see the effect in my screen saver. Using the "starfield" screen saver, I see the stars hesitate every second. Turn off either modem and the motion gets smooth. When I'm running in the games, the image hesitates every time the fps drops. Again, turn off modem and I run real smooth. Is my nic card bad? How does the nic affect video? Appreciate some help.