Sometimes while playing a game I randomly disconnect and then reconnect a second later. The game says you have been dropped then it instantly says you have reconnected, achievements have been restored. This happens very randomly. Sometimes I can play for hours and nothing happens.
Well what other games are you playing? Some games use a much higher amount of bandwidth than others. Try running at CAT5 cable from your router, see if that changes anything.
Lord of the Rings Online, Diablo 2, and League of Legends mostly. My DSL is connected to the phone and it will be a bit annoying to use a CAT5 cable just to play SC2 since my comp is so far away from the phone and router. My download speed is 2.61 mb/s and upload is .65 mb/s if that means anything.