This has been happening for about a week now, and is starting to get really frustrating. My connection is usually pretty stable, but for whatever reason I have been getting large ping spikes and timeouts.
There is a example of what I mean. When I use the command line ping repeater, my ping usually reads anywhere from 22 to 26 on a normal day, with vary little variance outside of that. When these large ping spikes happen, any streams I have going temporary stop (twitch.tv mainly) and any games I am logged in to will hang until the connection restablizes.
It doesn't matter if I have the modem plugged directly into my computer or going through a router, same behavior.
Signal data when modem -> computer:
http://i.imgur.com/h1ThMZX.png
Signal data when modem -> router -> computer: