Frequent Internet Drops - Have Tested with other Routers

For the last 24 hours I have been getting frequent (5-10 min) drops on my Internet. This usually lasts 1-2 minutes and only happens when my Router is connected to the Modem. I tried direct connecting a PC to the Modem and the Internet works fine, no difference in my normal speed. This led me to believe the Router was starting to go, so I replaced it with the same make and model. The drops persisted. I tried connecting to the Modem directly again, once again this solved the issue.

I'm not sure what would be causing this. I have a Motorola SB6182, provided to me from the Cox store less than 6 months ago. My Router is a Belkin N600 DB, which I previously used for ~1 year with no issue.

I have changed no settings nor hardware recently. I have completed virus scans on all my networked computers, no issues. No strange behavior has been shown with any of my networked devices recently.

Resetting either Router to factory default has done nothing. I'm at a loss for options here and am hesitant to just get a new Modem as it doesn't appear to be the problem. Options?