HEEELLP !

Does anybody know the cure for my high ping and packetloss ?
I´m on cable (512kbps) and when i try to play UT, the servers ping pretty good, 30-90 ping
then i start UT.and the ping starts to increase to over 3000 !! And on top of that i got packetloss from 4-8%...
I´ve tried to reinstall the game all the new patches.. different netcard drivers.. Win ME and W2K they all act the same
I´ve tested, 2 cable modem, cables, netcards,
D-Link and Realtech based cards, differen´t settings in windows ARRRRRGGAA !!!!

In UT i´ve also tried to change the netspeed but every setting over 2600, best suited for 28,8K-56k modems make
more problems for me
I have tried Quake 3 and this game seems to work better, not good but playable.. my ping there is close to 150...and
stable

I guess it´s something in UT that gives me this type of problem.. when i do the
net speedtest like the one at.. http://computingcentral.msn.com/topi.../speedtest.asp
I got over 500kbps it should be enough to play without lags

I´m posting here too becoz online gaming forum is full of guys asking for crack files and serial numbers..and if the the specific game is worth to buy bla bla bla

Help !! Soon i´m going nuts !!!