As I checked the cable signals, All the signals are in range.

Could you let me know whether you are experiencing intermittent/Slow speed through wired connection or wireless connection?

If it is wireless connection, I suggest you to change the Wi-Fi channels and monitor the same for the next 24hour so time.

To change the channels, follow the steps on the below given link:

http://arris.force.com/consumers/articles/General_FAQs/G34-G36-Changing-the-Wi-Fi-Channel

its both wired and wireless dropping out. Its only out for a short period of time normally not even a minute.

I suggest you to change the Wi-Fi channels and monitor the same for the next 24hours of time.

Also, Reprovisioning the modem with internet service provider after that if the problem persists, I suggest you to visit www.arris.com/consumersupport for further assistance.