Just found out xfinity could upgrade your Modem for free. Thanks Xfinity for the Wi-Fi boost. Never had the XB7. Went from the XB6 to the XB8. With instant noticeable improvements. :
Xfinity XB6-T Cable Modem Wifi Router CGM4140COM For parts | eBay
THE GATEWAY / ARRIS XB6-T WIRELESS MODEM, ROUTER, WITH VOIP TELEPHONE JACKS MAKES NOISE WHEN IT COLLECTS TOO MUCH DUST AT THE BOTTOM | Xfinity Community Forum
Gigabit Internet + XB6 Advance Gateway From Xfinity!!! - YouTube
Xfinity xb3 vs xb6 should you upgrade - YouTube
Xfinity XB6-T Wi-Fi Gigabit Router Modem Combo For Comcast For PARTS Please READ | eBay
XFINITY XB6-T CGM4140COM Modem For Parts or Not Working No Power Cord | eBay