"Quake 3 and Quake 2 Lag 999"

Hello,
I honestly need help on find out what the problem is with my cable modem. When ever my roommate logs into q3 online and I go into q2, both our connections jump up to 999 and stay that way until someone logs off the server. We have tried disabling the firewall and still 999, recycling the modem and have talked to our isp which they are never helpful in any situation. I was hoping someone may point me in the right direction on fixing this problem. I also tweaked my registry with the 98 download for windows from www.speedguide.net, I heard many good things but it seems like nothing is going well. Please if anyone can help it would be much appreciated.
Thank you,
Jacked