SteelHeart

1GB ram, 2GHz cpu, 230GB hdd from 1MB/s to ~380kB/s when playing a movie/game sounds like problem to me

What I noticed yesterday: when playing some game or watching movie on my PC, the download speed harshly decreases. I tried different media player, downloading by torrents and download manager, last night I reinstalled Windows (xpsp2+last updates), but the problem remains. Ideas?