Slow Internet Speeds

Here's the deal. My wife's computer is getting about half the internet speed of mine. We are both connected to highspeed cable internet using a Linksys WRT54GS router and a Linksys cable modem. I get 6300+ kb/s while she gets only 3300+ kb/s. Mine is an Asus AN8 SLI Premium using the onboard Nvidia nForce networking controller and hers is an Asus A8S-X using the onboard Intel 82540EM Gigabit LAN. The drivers have just been updated on her machine and all settings are at default. I have tried different cables and even switching the connector postion on the router with no effect on her speed. Am I missing something or is the Intel Gigabit LAN just that much worse than my nForce? Any suggestions on how to speed up her connection? I'm at a complete loss here

are you sharing the internet with her?