Had problems getting my old modem to speed up my contections using my internets providers modem until I switched to the Netgear Nighthawk CM1200. It helped so much in the speed I added the Netgear Nighthawk AX12 router WOW! Now its the fastest its ever been on the internet connections!
This modem is supported by Optimum for their 1GB speed. I provided the MAC address via chat and it was remotely configured by Optimum support team. The whole process took less than 10 minutes. I tested this modem with UPS power connection and the modem still works. I paired this modem with TP-LINK C4000 and so far no connection or restart issues.
In the end.....I found out that I had "excessive noise" on my Xfinity cable line. But I had to spend 4 hours online with a tech in (?India) and reconfigure the modem a couple times. It works fine now, but what a hassle