ARRIS SBG6782 Cable Modem & Wi-Fi Router

Even if I have a separate wireless router (Google WiFi), is there any reason that I should NOT shell out the extra $5 for the SBG6782 over the basic SB6183 without Wi-Fi? You know, just as a backup?

Also, it’s not clear from the description, but what features differentiate the SBG6900AC from the SBG6782 for almost twice the price?

The difference is maximum download speeds:

6183 - 16 download and 4 upload channels, 686 Mbps max.
6782 - 8 download and 4 upload channels, 343 Mbps max.
6900 - 16 download and 4 upload channels, 686 Mbps max.

Naturally, this also depends on your service provider. If your cable company doesn’t offer faster services, the extra capacity is moot for now.

Anyone know if This Modem/ Wifi router works with Optimum Online services?