Intermittent Internet Cutouts

[Rettere]

So I just moved to a new apartment (about 6 blocks from my old one) and transferred my Comcast Cable/Internet service. I had no problems with my internet at the old place. In the new place they replaced my old modem with a new one and rana 20-foot cable from the wall to my living room since the guy couldn't get the outlet in the living room to work. Now I get periodic outages of 2-5 seconds every couple minutes or so. Nothing long enough for my computer to say I am disconnected, just long enough to get kicked out of online games. I have tried this with and without my router connected- it seems less pronounced without the router but still occurs. There are spans of a few hours every other day where this doesn't occur, but most of the time I am plagued by 5-10 of these 5-second bursts every ten minutes. Should I blame the long cable? The new modem? Or something on Comcast's end?