I go in thru a router indeed. Its a Fritzbox (german product) with WLAN. i already shut down the wlan and hooked up with a normal LAN-cable - which actually decreased my ping by about 50 but didnt remove that lag at all.
I am running the minimum of processes, ICE. Did you read what i wrote to you? My specs are not an issue BECAUSE I CAN EVEN HOST A GAME WITHOUT SUSTAINING A LAG of this kind.
at least this forums seems quiet populated - hehe - thanks for helping me so fast :D