I have rather weird problem. I have no problem connecting to pantheon/custom games whatsoever, everything is smooth as it takes only few seconds to connect and can join every game, but when the game actually starts my packet loss jumps to ridiculous amount of 30-50%, which makes me disconnect of course.
I have forwarded both udp/tcp ports 6000-6200, turned off firewall on router and windows firewall, I'm using NOD32 and Spybot-SD as security software, but doubt those actually have to do anything with my problem and I can download from torrents without any problem.
Do you have any idea, why is that? Is it ISP related?