Have "Reboot" 3rd Party Arris Cable modem almost daily

I decided to stop "leasing" the Cox provided Cable Modem and I purchased an Arris SBG6900-AC

I also don't use Cox TV anymore and use a set top box for streaming my TV programming that uses the internet. My house is hardwired for I have cat 5 Jacks throughout the home and connect my Set top Box directly to Cat 5 and not using wireless.

Ever since I returned the Cox provided rental, I've had to reboot my Cable modem almost daily on some occasions 2-3 times a day, this didn't happen all the frequently with the Cox provided lease. So I called Arris thinking it was their modem, They ran their throrough diagnosis and testing and found nothing but due to good customer service, sent me another Cable Modem anyway. 

So I'm not on my 2nd Cable Modem and I still have performance issues watching streaming TV and dropping internet connection live Skype Meetings, Google Hangouts, etc.  Does anyone else have these issues using 3rd party Cable modem not leased through COX?