I just had a tech out yesterday regarding this problem on a TM402 - restarts under high network saturation (big uploads or downloads). According to the tech, this is a know issue. Comcast upgraded their network to support multiple carriers (called channel bonding) dynamically. Due to this upgrade, when your modem is demanding high bandwidth for large downloads, essentially, it requests an additional carrier (or channel)...when that request is initiated, the modem's hardware (and firmware) can't connect to more than one channel at a time, therefore, it "gets confused" and restarts itself to attempt to fix the problem. I upgraded to the TM602, and the problem is still there. This is because the channel bonding feature requires a Docsis 3.0 capable modem. The Arris TM702 is the first in the Arris line to offer docsis 3.0. I called Comcast and they are upgrading me to the Arris TM702 (which is a 50M down/10M up service, btw) for an additional $30/month - well worth it for the stability which I require.

As far as Comcast saying that it's fine, call them back with the information I provided, and ask to get you to a tech who can better service your needs...unfortunately, the "tier 1" techs don't have a clue.

The restarting of your modem is that the modem is bad or the power supply is bad call comcast have them send you a new one . Broadband will not reset the unit

Dana