internet freezes when i play games...

I have a PPPOE DSL connection and whenever I play games like ravenshield my internet stops. The light on my modem that says ATM turns off for like 10 seconds then the internet starts again. alot of the times it happens while im playing a game and it disconnects me from the server. it happens in alot of games, sometimes even when im just looking at websites too. anyone know what I can do to fix this? is the graphics card interfering with my internet? thx in advance